If, over a few years, they put out 5 or so decent adventures (not APs, just adventures), a monster book, maybe 1 or 2 player books, and 1 or 2 settings, it would be enough. For quite a while.
I think that's fine as far as WotC's product schedule, but I'd like to see an OGL that allows other publishers to create more diversity. As I said, it isn't about only having enough to play but options to choose from. The products you mention would give enough to play for most groups, but it wouldn't allow for choice. For instance, what about those people who don't want to play the Elemental story arc but don't have the time or energy or desire to create their own stories? At the least I'd like to see WotC open the door--sooner than later--for other publishers to create those options.
5E in no way "needs" new setting books-- "needs" as in "required to be made because otherwise DMs have no other options"-- because we have all the setting books we "need" on dndclassics.com.
Of course not, and I completely agree with you - at least so far as
my needs are concerned (although I would still
like to see new options for 5E). But in a way I think there's a bit of the car mechanic problem going on - when a car mechanic is trying to explain to a layperson about why their car. A lot is lost in translation from expertise to novice (this works in any field).
What about those folks who are relatively new to the hobby, who even started playing with the 5E Starter Set? Can you see how it would make sense for WotC to offer setting options?
I actually think Tyranny of Dragons was a bit of a missed opportunity, that what they should have done was combine the two relatively sparse hardcovers into one larger book (or perhaps three softcovers) and then offer a setting guide, a "Gazetteer of the Sword Coast" for further adventures or diversions from the story arc.
So again, while I like the approach of 5E for experienced gamers I'm worried about newbies...this seems to be one of the perennial problems for WotC, which they've failed to address so far with 5E. They need a clear path and package of products that guides people into the game, from novice to beginner, intermediate, and expert. The problem is that the people at WotC are experts, you and I are experts, so we know how to navigate the waters. But can you imagine being 12 years old and trying to figure this all out? A lot of 12 year olds will be able to figure it out, but I think they need to account for the many who need it spelled out for them.
Changing gears a bit...
You've got that backwards insofar as Paizo wanted to support 4E but WotC's delaying tactics regarding continued use of the OGL made that impossible. When WotC came up with the 11th hour replacement in the form of the restrictive GSL, Paizo cut ties and started working on a replacement backbone for underneath their Game Mastery products and adventures. Of course, no sense republishing the SRD without making some revisions and filling in some holes, thence Pathfinder. PF didn't come before WotC abandonment of the OGL. WotC's abandonment of the OGL triggered all of the things that caused their current situation.
This is a very crucial point. The success of Pathfinder was a perfect storm of a variety of factors, stemming more from WotC's mishandling of the GSL than the existence of the OGL itself. I really hope that WotC sees this, otherwise they might end up in a self-fulfilling prophecy situation: that is, by trying to avoid another Pathfinder they help create another Pathfinder. What they need to focus on, in my opinion, is creating a core product line that sets the quality bar and is easy to enter into for new players, and also offer an OGL that encourages participation in 5E.
As some have said, in a way 5E was a kind of "course correction" back to earlier D&D, a retcon heir to 2E that also manages to incorporate some of the best features of 3E and 4E. I hope that WotC takes the same approach to the next OGL - that it goes back to the basic idea of the 3E OGL but evolves it, rather than the reactive debacle that was the GSL. I hold out hope, but am starting to worry a bit considering the fact that we still haven't seen or heard anything.