Which of course raises the question of what WotC's goals are for D&D. That's what this whole debate is really about, since of course if they were trying to maximize revenue from RPG book sales they would in fact be following the Universe B model, while in the real world they are not.
Looking at what WotC's actions have been to date, I believe they have no intention of releasing a sixth edition. Ever. 5E is intended to be an evergreen game with a board game like release schedule, where in 2035 you'll still be able to walk into a store and pick up a 5E Player's Handbook. The game now solely exists to keep the brand from being explained as "this thing with dice people used to play" when discussing cross-platform stuff like movies or games with friends. If more casual players get picked up and turned into devoted fans of the brand, awesome - but they're valued as evangelists for the moneymaking parts of the brand, not a source of hardbook purchasers.
I like 5E a lot. I like the core books, and I also like the material they've put out in the recent Elemental Evil Player's Companion. If we get something like that every six months and see the monthly Unearthed Arcana articles get some playtesting revisions, that's all I'll need to keep playing the game indefinitely.
If you need more material than that to keep you invested with the ruleset, that's unfortunate, but none of us are WotC's target demographic anymore, myself included. You've purchased the product WotC has put out for sale (the core books) and if you're not interested in big adventure paths (which I for one am not), they're under no obligation to put out any further support whatsoever. The game is now complete - no one needs anything else to run it past this point, so anything we receive moving forward whatsoever is gravy.