This is an old whine. Jaron Lanier wrote along similar lines at least a decade ago. Part of it is nostalgia for the days when being a Musician in a Band was a Big Deal. That ended around the time Myspace got their millionth band.
How did we get stuck at rap and house? Big band came and went. Jazz came and went. Rock came and went. Disco came and went. House ought to be over by now, replaced by something totally different, like Balinese temple bell music. But no, house is still around after forty years, as various subgenres.
Speaking of Jaron Lanier: I actually saw him at BayCHI around 2000 or so, and someone asked him if Swing would ever come back.
He said, no, Swing was alive and things that are alive, die.
If you consider an artform like an ecosystem: there are epochs when many long-lasting species evolve and flourish, and others that are pretty barren. There's no reason to think that the general health of the ecosystem is always the same.
How did we get stuck at rap and house? Big band came and went. Jazz came and went. Rock came and went. Disco came and went. House ought to be over by now, replaced by something totally different, like Balinese temple bell music. But no, house is still around after forty years, as various subgenres.