Your central assumption is that I should select my gaming group based on people who game like me instead of, you know, gaming with my friends?
There's no law that says that will or must happen - but over time that's the way to bet.
I would like one edition that we can all compromise on. We don't glare at each other, because we're friends. We just disagree about what to play.
And gaming groups and individuals the world over disagree on the subject a LOT more than you likely will among your friends.
Also, as for the idea of supporting each and every previous edition of D&D at once? That's the kind of thinking that killed TSR.
Not so. TSR ultimately died as a result of 2 events - one million unsold units of the Dragon Dice collectible dice, and the return of unsold copies of 12 novels they published that same year (in previous years they only tried to sell 2 at one time). The associated fees with these events left them without cash to pay the company that not only printed but coordinated and shipped their products, who then naturally refused to do any further work.
It IS true, however, that prior to those events D&D had been on a downward slide for many other reasons. Too many products competing for customer sales dollars - part of which was the repeated production of new campaign settings (or revised versions of existing settings) which continued to earn less and less with each new one; players already having bought what they needed. It wasn't supporting new EDITIONS that were having that effect, but simultaneously supporting too many GAME SETTINGS. At the time of their demise the edition was 2E. Aside from the odd Dragon article or two, 1E hadn't been supported since shortly after 2E was released (less than a year?) and the 1E materials that HAD been in mid-production were either converted, cancelled or released.
TSR as a company had also come to earn a growing poor reputation among customers - products released and were regarded as poor quality, the whole website take-down order debacle, Lorraine Williams (CEO)reported disdain for their own game as well as the customers, the forcing out of Gary Gygax and persecuting his subsequent efforts, and of course the rising competition from other game systems (now MORE popular than D&D) that they had simply never had to deal with before.
I don't know if this whole Next thing
will actually succeed. I personally suspect it's more likely to significantly undersucceed (or fail) than it is to achieve its supposed goals of, "One Edition to Rule Them All". I think that if it
fails to significantly unite a lot of the "edition-warring" customer base that they will have no option but to support multiple
editions. Failure of 5E will have effectively proved that the market is permanently and intractibly divided between distinctly different approaches to playing the game that
demand multiple editions.
In short, we the gamers don't really need D&D Next (making it a tough sell as it is). WotC on the other hand DOES need D&D Next to be able to continue with the approach to the game that they've been operating under.