I'm a millennial, and I've been using VR for the better part of seven years, ever since the Oculus Rift S. If you look at niche communities like sim racing, flight sims, or space sims, you'll find plenty of millennials and Gen Xers who use VR extensively because it offers a level of immersion that a screen (or three) simply can't match.

I suspect your perception of VR users is somewhat skewed by 12-year-olds playing Gorilla Tag on standalone Meta Quests. There's a substantial enthusiast community outside that demographic.