I know this is a discussion forum, not a debating club, and so I'm not out just to score cheap points.
But the passage I've quoted genuinely puzzles me. Are you telling us about how you played (and still play?), and explaining how that is a viable alternative to "save the world"? Or are you making claims about "how it was in the day" and thus how "the focus of the game" has changed?
It's that second set of claims that I (and, as I understand his posts, [MENTION=22779]Hussar[/MENTION]) disagree with - because the game has never really been solely focused on KotB-style dungeon-crawling. In the late 70s there was enough "story"-style play going on that it made sense for White Dwarf to publish essays discussing the mertis of different approaches. While the section on successful adventures in the AD&D PHB is concerned mostly with dungeon crawling, the classes presented include paladins, druid and monks - all clearly best suited for stuff other than dungeon-crawling. The AD&D MM contains world-threatening as well as prosaic monsters (like the demon princes). And the AD&D DMG contains (limited) resources to support more story-focused or even epic "save the world"-style play (eg the artefacts and relics; the rules for divine intervention, which, to me at least, seem to have an Elric-ish inspiration lurking in the background).
And then there is the foreword to Moldvay Basic that I've already mentioned, which clearly intimates an approach to play quite different from classis dungeon or hex crawling.
The first set of claims - that it is possible to play a successful but non-save-the-world game - I take to be non-controversial.
What rules in 5e promote a "save the world"-type focus over a more prosaic focus.
(I know what rules do that in 4e - namely, the rules around epic tier - but those rules aren't present in 5e.)
How is it "at the expense of other styles"? What burden on anyone else's game arises from the fact that WotC publishes APs?
When I'm talking about the presentation of the game, I'm talking not only about what is written in the pages, but what is published as a whole, or what is not published, as well as what is presented as "official" or "semi-official."
So OD&D, for example, promoted a style where the DM created the world and the dungeons. That was the "apparently intended" style of play, because at the time TSR didn't promote an approach where you simply pick up the books, buy and adventure and play. Within that structure there were all sorts of play styles, but the "official" approach was that you made it up yourself.
For a new player, who says, "I've heard about this D&D thing, and want to give it a try" and decides to see what's available typically won't have a frame of reference as to what a TTRPG is. They might have played video game RPGs, but that's a bit different.
"So, OK, I need the Basic Set, or the PHB and maybe the DMG, etc. But how do I put it all together? Oh, I can buy a published adventure."
So they do. They like it, have fun, and buy another. Maybe a third. At that point they're ready to try their hand at writing their own.
Despite the fact that the DMG and PHB describe other play styles, they've been exposed by the publisher of the actual game to a single play style - "save the world." By not providing alternatives, they are promoting that play style by default.
I'm not saying that's good or bad, it's just the impression it gives (at least to me). AD&D up until 1987 "promoted" build your own campaign. Even the
World of Greyhawk was little more than a framework to get the DM started. Adventures might mention where they were in Greyhawk, which just pointed you toward that product, which gave you the framework to design your world. As I pointed out, B2 (and B1, and others), gave you specific instructions on how to flesh out the adventure, and Jean Wells and others have noted that one of the early design approaches they used was to include undefined parts of the area or dungeon for the DM to flesh out.
2e "promoted" a very different approach, especially as time went on. First, that D&D could be just about anything, although within the sword & sorcery base. Spelljammer, Dark Sun, Planescape, along with variations on the more traditional settings. But the big point was now that the DM didn't have to create anything - we have it for you. Whatever style you like, we have a setting, and adventures for those settings.
When I look at 5e, in the rulebooks and the published adventures, I see a more super heroic approach than a heroic approach. Level advancement, and gaining new abilities as you do, is the name of the game now. The expectation is that you'll advance in level every few sessions.
For example, in the AD&D DMG when it is talking about acquisition of spells, you are an apprentice to "a master of unthinkably high level (at least 6th!)" and I'm pretty sure it was Ed Greenwood that indicated that NPC levels were suitably inflated in the first Forgotten Realms campaign setting so as to be much higher than the expected PCs so they were always a challenge, and couldn't be just killed. I think that eventually backfired on them, though.
In 5e, 3rd level is really the new 1st level (when you select an archetype, although some classes do earlier). APs are designed to take you from 1st to 15th level in one grand adventure (although that trend was started in 3e if I recall). Contrast that to the AD&D adventures, where they eventually published T1-4, A1-4 (adjusting the levels upward to fit the new structure) and GDQ1-7 in a manner that you could run it as a single campaign with the same characters. That's 12+ adventures (depending on how you count T1-4) in three different adventure paths to do the same thing.
And no, it's not about "how it was in the day." It's just a commentary on how the overall presentation of the game by the publisher promotes a particular way to play the game. Yes, people will play it many different ways (one of the strengths of D&D, or RPGs in general). But new people picking up the game for the first time are steered or at least nudged toward a particular style of play. That does mean that "how it was in the day" is probably different, generally, than today.
You're a fan of Story Now games. They are more specific in their focus than D&D ever has been. It would be difficult to play a Story Now game with a strict sandbox/hexcrawl/dungeon crawl approach with no story input from the GM. In fact, it's really against the design goal of those games.
Like all designers, those that designed D&D had their intentions as well. Their concept of what D&D is, and how to play it. It's not nearly as focus as some newer games, but it's still there. Dave Arneson had a different opinion than Gary Gygax, but they still had their concepts. As I've said, Gary didn't see any point in publishing adventures initially. That's not how he intended for the game to be played. But the players of the game thought differently, and the game changed because of it. But that doesn't change how the game was presented at the time.
The potential impact is primarily on new players coming to the game. Since it's a social game, that impact can be lessened (although I see it all the time when I meet people who learn to play via the 5e rules without much or any guidance or input from other gamers). Like any gamer, I like to find other like-minded players to play with. It doesn't mean I'm not willing to change, or expand my horizons (although I'm admittedly much less interested in that now than I was 30 years ago). It was far easier to find like-minded players in the early '80s than it is now. I can find more players, they are everywhere. And that's awesome. But they often have different priorities and play styles in mind. They seem to be everywhere online, but not local to me, and I'm not interested in running an online game. I prefer a face-to-face game.
When I teach new players to play, then I usually find that I also have like-minded players. Because they've learned it from me and my style. But that's me promoting it, not WotC. Most of the players I've taught continue to play, and a good percentage of them eventually gravitate to being a DM because they aren't finding other like-minded DMs.
A stronger impact is when I try to play with folks that first learned D&D with 4e. For many of those players, my style is just plain incompatible since I don't use a grid, and everything is theater of the mind. Again, this is a direct impact of the way the rules were written and presented. I also find that it's like pulling teeth to get them to tell me what their character is actually doing, rather than ask, "can I make a <insert skill here> check?" My play style is foreign to them, even though we're both playing the same game.
Overall, though, I'm only commenting on this in relation to the OP. The OP was saying that it doesn't always have to be "save the world." Something I agree with. But I think that part of the reason DMs seem to write more "save the world" adventures, is because that's what they are used to playing.
You could say it's a chicken/egg thing. WotC is publishing "save the world" adventures because that's what sells, but since they don't publish anything else (for the most part so far), then they can't really know if other things sell or not. And the "save the world" approach started long before 5e. But it was not a common approach up through AD&D until probably Dragonlance. Even the GDQ series wasn't really a threat against the world, or at least it wasn't presented as that type of campaign. When you started G1, there was no indication that you might eventually fight a demigod 7 adventures later. And that's assuming you cared to follow the storyline to each subsequent adventure (or that the DM cared to). And if what you have to go by is the published materials, then is certainly seems like 5e is a "save the world" type of game.
