I'm really of two minds about this. The pessimist in me fears that what you are saying is true, and that this "radio silence" is the 5E version of the mishandling of D&D, and WotC is only going to keep the game afloat and focus entirely on licensed stuff.
I feel like I see a lot of comments on this forum to the effect of WoTC "mishandling" 5th Edition, and I am curious, when I read them, how much of this is because the authors are not
currently getting what they want out of their game at the table, and how much is a general perceived sense that the RPG as a whole is suffering?
In other words, how many people out there are wanting to play D&D 5th Edition, but choosing not to, because there are not enough D&D 5th Edition products available. Or, even worse, how many people picked up, say, the starter set, said to themselves, "this is a fine roleplaying game!", but then went back to playing another game because there weren't enough published adventures, settings or character options to choose from?
For myself, I am a relative newcomer to modern D&D, having played as a kid, but completely walked away from the hobby for my teens and early adult life. I played a little 4th Edition, but then heard about D&D Next and decided to wait for that to come out, then picked up the starter set as soon as it came out. While waiting for my starter set group to come together, I remembered my old copy of Keep on the Borderlands and realized that it would be pretty easy to run it using the 5th Edition rules. I ended up running it as a campaign on Roll20, and we've been running that same campaign for over 6 months now. It's not hard to google up many lists of "best D&D adventures", and now we're playing Castle Amber, which I purchased off dndclassics. I grabbed a couple of the Mystara gazetteers as well, and we might just run some homebrew adventures after the group makes it out of Chateau d'Amberville. There's definitely some work to come up with monster stats for X2, because many of the Mystara monsters are not in the Monster Manual, but it's not so bad. And, honestly, when it comes to new DMs, I don't think the problem is bad monster mechanics. Our games suffer because of bad listening, bad improvising, etc. Not because my Rakasta had the wrong to hit bonus or a stupid trait.
So, yes, I would love more 5e adventures to choose from, and I'd love some well-made 5e campaign settings, possibly with custom classes and races that make that setting feel unique. But I don't think the lack of them is going to stop me from playing the game, at least not in the near future.