In high level you can't playtest what the players will do.
Sure you can. It just requires time and effort, which WotC has rarely been willing to put forth. They literally didn't even bother testing 3e past the first handful of levels. That's why E6 works the way it does. They actually
did test those levels, and lo and behold, those levels actually work! But the balance breaks down rather conspicuously within just a few levels. Because they simply weren't tested.
To say they haven't tried and they've half ass tested it is an arrogant statement at best.
Good thing I didn't then. 4e cracked it, by
actual testing. 1e (and thus mostly 2e as well) also did well, but because of the awful organization, intentional obfuscation, and simple inexperience (the hobby was brand-new after all, we can't expect perfection), it fell short in some key ways. For the time, it was actually a surprisingly well-balanced game.
Thing is the whole point of DND at creation was it could adapt to ANYTHNG because it had a DM. That leads to insane power creep at high levels. It was a design choice.
Nah. D&D is much
more limited than several other games that are in fact better balanced than it. The issue is not, and never has been, the potential range of actions players can attempt. It is, and always has been, issues with furnishing certain archetypes with nearly absolute power, while chaining other archetypes to a sharply limited range that is actually
smaller than what real flesh and blood people can achieve because "realism" or the like.
Now at lower levels some of the 3rd to 5e design choices on removing restrictions from magic and never ending combat cantrips minimize the biggest advantage of your three in that they can reliably output predictable power far better than a mage even when all cooldowns are blown.
I don't understand what you mean here. What are the three advantages of mine that you mention? 3e did not have "never-ending cantrips," though believe it or not I'm perfectly fine with those, it's other things I take issue with (mostly, but not exclusively, things like spellcasters getting to literally rewrite or lock down
reality itself, while Fighters and Barbarians...hit slightly harder, slightly more often.)
If you want to see the only edition that actually plays magic the way you seem to want it,
You have made an incorrect assumption. I don't, strictly speaking, want magic to be any specific way (though I do believe that between-edition power creep has made magic excessively powerful and people are much too precious about it.) What I want is for the designers to stop wasting 2+ years just figuring out the
absolute baseline parts of their systems, as actually did happen with 5e (remember D&D Next's "specialties"? Or the "proficiency die"? Or how Fighters got redesigned every other packet until just before the public playtest ended?) Because they absolutely COULD have done plenty of testing at higher levels if they hadn't dithered about for almost two years before finally settling on their core design.
play 1e ad&D an edition where if your party doesn't protect you you won't get a single spell off unless the dice do crazy things or PF2e where magic has been relegated to support and nothing else.
Nah. The lethality of 1e is not a good fit for the modern gaming audience, for exactly the same reason that original EverQuest, despite having provably been one of the best-selling MMOs ever, would absolutely be a monumental failure if you tried to launch it today. The form and pattern of difficulty presented by 1e is a problem for D&D players today, who either are older and thus have less time to dedicate to gaming, or are younger and thus have competition for their interest from other, newer things that give similar levels of satisfaction and rewarding experiences with far less onerous requirements.
I haven't played PF2e, but it has been recommended to me for unrelated reasons (that is, regarding the tactical experience, not the power level, whether generally or magic specifically.) I have been leery because it makes some design decisions I'm not super keen on, but in fairness, I do believe that some design can play better than it looks like it would. But I don't really have any interest in "magic [being] relegated to support and nothing else." The fact that you think I DO want that is part of the problem: you are forcing an unjustified binary,
either magic must be absolutely phenomenal cosmic power with practically no limitations, OR it's been "relegated" to a tiny almost insignificant role.
There are other options here.
Survey's repeatedly show that almost no one does high level play.
And what if you have the conclusion backwards? What if people don't play high level
because the rules suck and there's no adventure content, rather than because nobody has any interest in doing so?
That would make your claim completely circular.
IT's pretty easy to see who has actually put some effort into high level games (by the rules) and who hasn't. Most of the things argued about how abilities work in game never work they way the do in the forum arguments. Especially with magic.
If you wish to accuse me of falsehoods or fictions, do so. Otherwise, I will simply ignore blanket aspersion-casting like this.