Instagram/Tiktok has lots of young people getting bikes. Unlike earlier generations that grew up outside dirt biking,riding bikes around the neighborhood, and working on things in the garage they have largely grown up inside. Covid didn't help. I'm mid 30s and I'm right at the edge of the change. We had Myspace but Facebook wasn't a thing until I went to college. A lot of kids who are getting bikes are learning skills from the ground up. When their bike breaks it's a crisis, not a get out the haynes manual and fix it thing. They don't have riding skills from hanging out unsupervised on bikes in the neighborhood. Some of them value looking cool on the bike over being cool on the bike. It's just different. There also weren't speed cameras, flock cameras, and nearly as many cops back then.
I rode with a group to the tour de bay or whatever that ride is from Pleasanton earlier this year and the group was massively varied. Nice people of all ages. Motorcycling is fine, but hardcore group rides aren't. My buddy and I keep it tame on the street and get our jollies out on track.
)... however, there are plenty of young people that ride -> they are just not here, unfortunately.