Sherry, I had about 750 followers before ever becoming a contributor to medium. I’d been a (non-paying) member for years. I’d written one somewhat boring but positive comment on a viral article, not realizing comments here were treated like stories. From that one stupid comment, I got 750 followers, over time.

Not saying that’s the case here, just one possible explanation. Comments are no longer treated as stories that show up on your profile, I think, so it may explain how someone can write things, but not appear to, and still garner followers.