[vintermann]

YA, like "New Age" 30 years ago, is not a genre. It's a marketing category.

Marketers built a profile of the buyer they want to target in their minds - a glorified stereotype. The buyers themselves didn't identify with the label.

But the marketers then demanded products tailored to this stereotype. And of course, many authors caught on, and were willing to move towards the marketers caricature of what they had in common, in order to get access.

So there's no co-option here. People are just fighting over a marketer-created niche. The niche is a bad fit to reality (in more ways than the audience hardly being young adults) but it's got enough money behind it that it's not easy to challenge it.