So this makes me wonder, could WotC actually make the majority of people happy with a new edition?
In order to have any chance at creating a new edition that would make the majority of people happy, you would need a system that included---
(a) The cleaner math, simpler prep, dynamic combat options, and many of the other features of 4E; with
(b) The gameplay that was marketed as D&D from 1974 to 2008.
I believe such a game is theoretically possible. OTOH, I don't believe that WotC has any interest in creating such a game.
And even if they did, there's a lot of ancillary work WotC would have to do at this point to start healing rifts. At the very least, they would have to improve the quality of their support products; reverse several of their unpopular decisions; and generally show a higher degree of respect for their customers.
I'm not convinced that WotC -- as an organization -- is interested in or capable of doing any of that, either.
Plus, you may be right. That may not be enough. The reality is that people who like pre-2008 D&D are playing the best supported RPGs in history with new, high-quality support coming out every single day. Given that those people legitimately enjoy the game they're playing, it's not just enough for WotC to produce something that's better than 3E at providing the pre-2008 D&D gameplay. They have to produce something MUCH better in order to counter-balance the advantages of experience and support the older system(s) have.
That could be done in 2000 with 3E because:
(1) The older edition could be taken out of print. (The OGL stops you from doing that.)
(2) There was widespread dissatisfaction with the AD&D ruleset, including a substantial body of ex-D&D players who could be brought back into the fold by fixing the problems they had with the rules. (WotC thought they had identified similar dissatisfaction with D&D3, but the proof is in the pudding: A significant portion of that fanbase wasn't dissatisfied with the stuff WotC that they were dissatisfied with.)
(3) Although there was a large body of existing support material, WotC could also take that support material out of print. (The OGL and digital distribution have taken that option away. And it was still only a fraction of the support material that now exists for 3E.)
(4) TSR had created a great deal of bad-will. WotC was a new company and could make a completely clean break from the past.
More fundamentally, I think the nature of the dissatisfaction in 2000 was significantly different than the dissatisfaction that now exists: There was a fairly widespread consensus on what the problems with the AD&D ruleset were. And most of those problems could be fixed without eliminating the core gameplay of D&D.
In 2008, WotC addressed a different sort of dissatisfaction and fundamentally changed the core gameplay of D&D. In a world without an OGL, this would be a mistake. In a world with an OGL, it may be an irreparable one. Paizo now owns the segment of the market that fundamentally likes 3E but wouldn't mind seeing it improved in a variety of minor ways.
How can you win that segment of the market back? I honestly don't know. Big changes won't do it. Those players specifically aren't interested in big changes. And big changes also means divorcing yourself from the massive 3E support network, which gives you another huge hurdle to clear.
But small changes won't do it, either. Small changes won't justify making the switch back from Pathfinder. WotC can't even really offer the advantages of "official support" because Paizo is out-producing them in terms of quality products.