I'm not that old, but the first time I'd ever heard of Only Fans was about a month and half ago. Someone from my high school class set up a facebook page for a reunion a while back. For the most part, it's now used as a way to communicate that a classmate or classmate's parent/sibling/significant other passed away.
One of my classmates posted something about a guy we all knew passing away and had picture in the post. I clicked on it and noticed it was a woman standing in a hallway with skimpy underwear on. I sent him a message and asked him what that was all about - he said he meant to post a photo of our friend, but somehow posted a screenshot of an Only Fans account he was watching.
He's lucky he was online when I sent that note - he immediately deleted it and as far as I know, no one else saw it. It was weird for about a week after that. He sent a note thanking me for catching that and then a few days later he reached out about concerts I was going to see this spring, wondering if we'd be at any of the same ones. That was weird because outside of occasionally liking stuff each other posts, we haven't really communicated. I think he was just trying to gauge whether or not I thought he was a perv or not.