Like how music went through this phase where "not mainstream" music started getting really cool but now all of those sounds are just what everything sounds like now, you can't rebel against mainstream music right now.
What changed is there is no new "underground" culture to take the place of what had become popular and mainstream.
Witch house in 2009 or so I think was the last gasp of the underground before shortly running out of air.
Now young people just doomscroll tiktok instead.
Lagniappe: https://www.youtube.com/watch?v=HQxq_-dWYsc (in the fine tradition of pastiches combining video with unrelated audio)
A new subculture either grows or dies, if it grows people start making money off of it and it gets diluted by the popularity into something more beige and palatable. It isn't about capitalism it's just when you add more people, they take it less seriously and hardcore becomes bland.