I think that's a little fast, production wise, but your point about the first adopter pace is well taken. I was shooting for the trailing edge of first adopters or the very beginning of mainstream advancement, but I can see the utility of moving faster.Your schedule isn't fast enough to keep up with the general (and expected) pace of play these days.
I'd think something like this would work better:
Year 0: Core Rules (Lvl 0 - 10), Starter Set (Lvl 1-3), normal launch products
Year 0.5: More core supplements; Advanced Core (Lv 11 - 15); Advanced Core supplements (Domains? Army Battles? Organization?), Guide to Fiends (and similar mid- to high- level opponents), Guide to Dragons(?)
Year 1: more Advanced Core supplements (Planar?); Heroic Core (Lv 16-20)
Year 1.5: a few Heroic Core supplements; Epic Core (Level 20+)
Ditch the Monstrous Humanoids piece (please!) and otherwise combine books 2 and 3; and release the set of four at a rate of one per six months. That way, the subsequent books after the first one will hit the market right about the time the first-adopter groups - and there'll be a lot of these - get to those stages, assuming a typical WotC-era pace of level advancement.
Some of the supplements might be able to be put off a bit, so as not to staurate the market with too much too soon.
Likewise for combining the Advanced and Heroic portions. I think quality-wise we'd be better off a little slower for those two in particular, especially since those are the areas/levels that are suffering the most from lack of attention currently.
And saturation is another reason why I had a slightly slower cadence. Really, though, aside from the Core, the sample Adventure Path, and an Opponent Book, the remaining supplements can come at any pace. So maybe put those on the faster cadence, and the others slower?
I'll admit the name for the first opponent book is sub-par. Nor do I have very good memories of 2e's version, and Savage Species was only a little better. It was more listed as an example of "How to Play/Detail the Typical Opponents", not as a PC-options or MM book. I mean, for all the meme-talk about Tucker's Kobolds, or the Red Arrow (?) Orcs from Faerun, have you ever really seen any guidance on how to play those kinds of opponents well? Or how to make them relevant through an entire campaign? (Sorry. It's an issue of mine. But worth thinking about, I feel.)