Maxperson
Morkus from Orkus
More than 50% of 5e players are new to D&D, and this edition has massively expanded the marketplace so much that "what players from other editions think" is not even a major question for WOTC anymore (in fact Jeremy Crawford recently implied that with the cancellation of the Revised Ranger - the player base expanded so much with new players who think the PHB Ranger is fine in just the past couple years, they don't even feel the pressure to address it anymore). It's probably outsold the first 4 years of 3e+3.5e+4e COMBINED I think at this point. You appear to be woefully behind on your information, stuck on prior editions and thinking we're "early" with this edition. We're not. It's well into this edition and having the best sales year ever in the history of D&D right this year.
Think about that: This year of 5e is literally a better sales year than the first year of 3e, or 3.5e, or 4e, when the PHB had just come out. Heck I think more people are WATCHING D&D played online by others than even played 4e in total! It was on the friggen Tonight Show a couple days ago!
Appreciate for a moment the monumental amount of sales they're having. This is a unique time in history - this hobby has hit mainstream. Consider the possibility that millions of people really DON'T want something different than this - they really do want this, and the preferences of people who even know anything could be different about the game are a tiny minority at this point.
Feeling like an edition has left you behind is a rough feeling and I genuinely sympathize with it (I've felt it before too). But there are so many other options out there. Why beat your head against an edition that really isn't going to match your preferences in terms of content output?
So nothing you've said that impacts my point at all. I don't think those 50%(I'll take you at your word since you've provided no links) of new players are ignorant and unable to understand that just because they only know the current release rate, that other rates are not possible. Nor do I think that a lot of them are unable to like the game, buying the books released, and yet somehow be unable to want more. It's very likely that a lot of them would enjoy more books. So while the sales is higher than ever(again you provided no link showing this to be true), that doesn't mean that sales wouldn't be better with a release rate that is a bit higher.
I don't feel left behind. For that to happen they'd have to have a release rate faster than a slug.