Alt spent much of the 2010s dominated by the hipsters - probably related to the backlash to the aggro 2000's. Lots of folk and indie in general.
Alt also stayed hipster-friendly in the latter-half of the 2010's by going with avant-garde pop music (following in the footsteps of Lorde). You can tell that 2021 is a different year because the hipsters are furious at various forums and websites, complaining at a level I haven't seen since maybe 2009-11.
As someone who was a teenager during the 2000's I can only say that Alt changes every few years and unless your favorite artist has a timeless sound (or is a huge hitmaker) they're not going to stay relevant on Alt forever.