There is this strange notion that D&D players are a monolithic group, that (almost) everyone plays one version of the game, one set of rules, with little variation.
Now maybe this is more true today than it was in decades past. Maybe the current boom of "Stranger Babies" (post-Stranger Things) tend more towards playing the RAW, and sticking to whatever WotC publishes - I have no idea.
But part of the problem, and perception around "splitting the fan base," is the idea that either we all cohere around the same set of rules and book, or we're "splintered." Or that it isn't natural for us to splinter off and diverge - or customize the game to our liking.
Meaning, I'm questioning this notion that the player base is or should be moving lock-step from one edition to the other. Rather, what if D&D is more like a tree, that branches endlessly, and each "blossom" at the end of a twig is a single game group?
There will still be, by default, a central limb or branch from which most campaigns blossom. But even within that, there is great (endless) diversity.
I think back to an aspect of WotC's marketing before 5E came out. They said that everyone was invited, that D&D was more than just one edition or set of rules. They even made impossible promises that they couldn't keep: that everything would be compatible with 5E, everything supported. To give them some credit, this isn't entirely false; they opened up the past library for download, they created DM's Guild, etc. And of course there's only so much that they can do; providing rules conversions for every edition of D&D for every product is simply not worth spending their resources on.
But I think the spirit of "we're all D&D players, everyone's invited - if you want to use this, hopefully you can, but if not and want to stick with your hybrid TSR game, that's fine too" is a good one.
In fact, if I were to WotC, I would double-down--again and again--on this tenet: "Make the game your own. We'll provide the core rules, and keep adapting them to what we feel like represents the current player base as much as possible, providing new settings and adventures that explore the possibilities of the game, but we're not excluding anyone, and even if you play an older version of the game, or a hybrid of some kind, hopefully you can use what we publish in your game in some form or fashion."
In other words, not only normalize hybridization, but advocate for it. The core rules are just something to improvise off of, to whatever degree you like. In fact, what is "core" is your game.
But it is also on the fan base to respond in kind. There are always going to be people who are disappointed with the current state of the game, whether because they preferred the version in (what they imagine was) the D&D of 24.271 years ago (or whatever), or because WotC is going in a direction that is further and further from what feels like 'D&D to me." Some of this might be warranted, as change is not inherently good (or bad) - but to some degree this implies a certain degree of stubborn entitlement, as if it is WotC's responsible to cater to my preferences, whatever they are.
This is, of course, impossible - not simply because they can't please everyone all of the time, but that--by economic necessity--they have to remain focused on their actual, current demographic.
Things change. The game moves on, and the base is different now. By my estimations, more than half of WotC's estimated 55-60 million people who have ever played D&D, started up since 5E began. That's 30 million or so players who are Zennials or cuspy Millenials (say, born c. 1995 or later). And of the remaining 25-30 million who started earlier, probably only 5 million or so still actively play or purchase products.
(The exact numbers aren't important, but the main point is: there are many times as many newer players than there are carryovers from earlier editions).
So maybe "splintering" isn't such a bad thing? At least if we embody that spirit of "everyone's invited," which means that all versions of D&D are valid and fine, because they're all part of the same tree that is the ever-growing tradition of D&D. Meaning, maybe the negative elements of splintering--the in-fighting, the "if you don't like this, then you're x," or "if you like that, then you're y"--could be jettisoned, but that's at least somewhat--if not mostly--on us. It is WotC's job to set the tone, to provide the context of the game as it is today, but that still means that a lot is up to us.
