I disagree. Gygax pushed Greyhawk in AD&D. Mentzer was built assuming Mystara. 3E and 4E came with built in gods. And 2E had some nice stuff like the Campaign & Catacomb Guide or Villains Handbook, but not much built into the core, plus a setting deluge spearheaded by the Forgotten Realms.
D&D's saving grace as a construction kit was a baseline implied setting that drew on enough mythology, pulp fantasy and Tolkien to have done enough foundation work to support most people's idea of what swords & sorcery was, even if a few anomalies did creep in (e.g. clerics, oriental monks). From that baseline, innumerable frustrated fantasy enthusiasts found a departure point for creating their own worlds and playing their own adventures.
No D&D takes players by the hand and goes something like, "this is an elf. You might want to build these subraces for your world", with the result being Johnny's purple, jungle-dwelling Feral Elves and Johnny thoroughly invested in the game, because it's not Gygax's Greyhawk or Mearl's Nerath, but Johnny's World of Magerizing. Or something like that, I don't know the details because it hasn't really been done. The most support given to homebrewing is stuff about town demographics and wandering monster tables by climate, that sort of thing. Not exactly riveting stuff compared to the apple the designers themselves bite into.
But it's a core appeal of D&D. If you want someone else's world, there are CRPGs, comics, novels, movies and MMORPGs aplenty to service you. D&D appeals to an audience of creators, at least in the DM's seat, and the players wouldn't be there save for the passion of that person for what they've made.
If I am a novice gamer, the appeal to me to do all kinds of crap to have an elf in a unique world makes my eyes glaze over. It's boring. I just want to play al elf in a cool world. I don't care how much you think it's virtuous to make my own world and elf mini-culture based on vague implications.
If I am an experienced gamer, that vagueness is equally useless, because it's less than what I can come up with myself. If I am experienced gamer, I want a more detailed world, because the more stuff there is, the more I have to choose from. Any detailed campaign setting is a smorgasboard unless I want to complain on the Internet about how Elminster's existence oppresses me.
Your approach fails new gamers and old. We've seen it tried. WotC had a chance to show us how awesome D&D would be with the world moved backstage and replacing it with rules mastery. This has proven to be unsustainable. In fact, even the period we could as success seems in hindsight to have been a period largely fuelled by self-delusion at all levels of the hobby. The D&D hobby did not need to reach faddish levels again -- it needed simple sustainability. 3e failed to provide even this, and having amputated itself of the ability to produce decent narrative content, WotC resorted to ever more convoluted extensions of the rules mastery principle, along with rebadging to disguise the inevitable supplement treadmill -- inevitable because little brown softbacks were obviously a failure, and by 2002 pretty much everyone who wanted a PHB had one. 3.5 was a manifestation of these issues. Eberron was an example of how basic flaws in creative leadership led to the squandering of obvious talent. (As I have said before, my view is that Paizo basically does the same thing -- makes creative people make uninteresting things.)
4e was a ground up revision pretty much because it needed to be, and in the process it absorbed a bit of fashionable nonsense promulgated by terrible gamers, but it still managed to be brilliant in its design. It just wasn't interesting as a thing that connected people to a world, and to fiction of their own devising. It lacked some critical ambiguity as to whether it was creating the basis of the fiction or the beats of the fiction. The OSR proved that this was still a cherished value, even at the expense of game systems that, honestly, really are kind of better.
What I'm talking about is something often expressed in edition wars. I love 4e, and it is totally true that you can rationalize 4e systems in the world in all kinds of cool ways -- but 4e's text seems utterly unconcerned and reads as almost dismissive of this kind of thing. This reproduces the decade-old failure to understand that even though rules matter, it isn't really all about the rules.
D&D basically suffers from a dearth of meaning now, and WotC doesn't seem to know how to fix that. D&D's image is cheezily self-referential in a way that reeks of coded self-contempt.
Before 5e takes place, WotC needs to get its community building on. It needs to rebuild the idea of a D&D hobby as something other than a bunch of balkanized gamer tribes, one of which it throws its weight behind. This might take years. It might even be a good idea to just shut D&D down completely for a while. 1 to 2 years might do it. After that, it might be able to come back without so much of its damaged legacy to be greeted by gamers who actually want to see it again. I'd go for easy to learn but extensible rules, some return to atmospheric quirkiness in the system (especially spells) over rigid principles, and at least one world with decent support and a strong place at the front of D&D's image.