I barely know a single person IRL outside of tech who uses reddit and I'm a millennial. Like, they know about it, and occassionally reference a post on it but they aren't on it anywhere near like my friends on instagram. My millennial friends are on instagram 24/7. I might make a story once a month and as soon as I post it I have 100+ people who have looked at it. And I have so many friends who post stories every single day. They're on it non-stop during any idle time.

Reddit has an atrocious new user experience. That's why Digg was so much more popular and reddit was incredibly niche until digg died. I didn't use reddit pre-digg-death because I had no idea how it worked it looked so confusing.