Marketing isn't just advertising; it's also product design. Outside of a handful of very, very boring products such as rice, drinking water, and toilet paper, there aren't a whole lot of things that have universal appeal. Changing your product to appeal to one group can and often does mean it becomes less appealing to some other group.
However, overly focusing your product on the people who spend the most money is a very late-90s thing to do. This was conventional B-school wisdom at the time, but most people have moved on. If you focus on the people who spend the most, you're focusing on established customers who already spend a lot of money and not doing anything to attract new ones.
The comic book industry basically destroyed itself by doing that. What we saw in RPGs and comics in this era is that by becoming hyper-focused on hobby shop enthusiasts, they failed to attract kids and thus create new fans. The reason 4e got made to begin with, and made the way it did, is 3rd edition was failing to attract new customers, and the splat machine ran out of its ability to print money startlingly quickly. WotC knew they had to get new players or die...and from what I read, 4e was quite successful at that. Problem is, it drove off a lot of old players, too!
Which is why 5e was made. 4e was INCREDIBLY successful in bringing in new, younger players who had never played D&D before. But it didn't have the technological tools or the cultural zeitgeist to capitalize on that new market, and it also fractured the current player base (something that was bound to happen anyway at any new edition change, and especially due to the mistakes of the SRD 3.0 & OGL and the burning of bridges with Paizo).
5e comes around, is developed with years of playtesting by fans of ALL previous editions in order to reconcile the broken base, has the technological tools to actually capitalize on the pdf and digital markets to make a SRD 5.0 actually WORK in WotC's favour (something 4e STRIVED to to do but WotC failed spectacularly with at every step of the way), and came into being alongside Twitch stream culture and in a world where Adventure Time and other mainstream media actively encourage fantasy roleplaying in people of all ages, rather than treating it as a niche, nerdy hobby to be shunned. It also has absolutely free rules to start, and methods for the DM to buy books digitally for the whole group without getting into the nebulous legal-issues of "circulating the tapes." There's never been an easier and cheaper time to get into D&D.
This is why 5e has to have elements of 4e in it (like Tieflings and Dragonborn and Battle Masters and Avengers-in-All-But-Name-Paladins and AEDU Warlocks in the Player's Handbook), to the chagrin of many 3.5e and earlier fans. 5e is the Nintendo Switch to 4e's Wii U. It's the Smash Bros. Ultimate of D&D editions: EVERYBODY is here (or at least that's the intention).
Every new edition of the game is going to either react to or build upon the previous editions, and I'd argue that they all do some complex of both. That includes 3rd party forks like Castles and Crusades, Pathfinder, 13th Age, and Adventures in Middle-earth. 5e found the happy medium in doing so, where it was able to learn from the lessons of the past editions and retain as many 4e players as reasonably possible, bring back into the fold as many older-edition players as reasonably possible, and bring in as many new players as reasonably possible.
3e had a huge data-driven survey ahead of its development. But that was in the late 90s. Big data has come A LONG way since then, and most of us are freely and passively giving up our data to online aggregators when we're not actively doing so because we WANTED to influence the creation and ongoing development of 5e. Big data is EXTREMELY important to a company's profit margins, and Hasbro was about ready to fold the D&D division of WotC several times through the lifetime of 4e, because the data they had used to project what would sell in 4e didn't meet the realities of supply, demand, price, and technology of the time.
DMs Guild is built in such a way: the more a product sells, the more its promoted by the system, and the more closely WotC scrutinizes whether they should be getting in on the $$$ with their own official version or something in that vein. That's WHY the semi-official Guild Adepts program exists. Why do you think Rune Knight Fighter and Noble Genie Warlock were in Unearthed Arcana after they showed up in Xanathar's Lost Notes to Everything Else? WotC saw a product that was successful, and archetypes that people liked, but might be able to do it better and to a wider audience.
That DOES NOT mean everyone will get on board with it. If you are not happy with 5e's official books (not to mention the wealth of options and tweaks available from DMs Guild, DriveThruRPG, and physical 3rd party products), then, yeah, it might suck to be you right now. But you'd be the exception to the rule; dare I say, the exception that PROVES the rule. You're not the target demographic, because you're happy with an older version of the game. Do they want to figure out a way to make you buy 5e? Sure, you could be a peripheral demographic – but only so much as you might buy what they're developing. And they're NOT going to spend resources developing material that ONLY your peripheral demographic is going to buy. To that end, they're not even going to open the DMs Guild to developing OD&D, Basic D&D, 1e AD&D, 2e AD&D, etc because that doesn't serve the data scraping purposes that are even more profitable to WotC than the fraction they get from every sale on the website. Your old editions just aren't worth the $ and time granted, and every dollar and minute the team spends on something that isn't the most recent edition is money and time lost from Hasbro's profit margins, and inches granted to competitors like Paizo that are attempting to push back into the market that has been dominated for the last few years by 5e.
I'm not saying I want Pathfinder 2 to fail, or that leaving you out to dry is a good thing. But it does not serve the market interests of WotC, and liberal allowances toward 3rd Parties to use their proprietary content is party of what allowed them to lose the 3.5e player base in the first place. They're not going to actively or passively TRY to split the market. They're going to do everything they can to CONSOLIDATE the market. And that means, they'll sell you ALL the back content from old editions on DM's Guild. But they won't make new content for obsolete editions (obsolete in terms of their market priorities, not in terms of playable or not). They might make special editions of old books again. That's like collector's goods. They like that – Beadle and Grimm have been very successful licensees for special edition collector's goods. But they won't develop for multiple editions.
Maybe in an ideal world, 6e will have rule system sliders to allow play to look like any previous edition's complexity. That was half-promised for 5e, and not met as it eiter didn't playtest entirely well or was going to be too much work in the face of meeting the goal of release by D&D's 40th birthday. Maybe there's an R&D team working on that still. But I wouldn't put my chips on it – at least not while 5e is still selling like hotcakes.
