I left the day Elon took over, but there are a lot of marginalized/unique social groups still on X that haven’t migrated to other platforms. So I know some people stay because they can’t find the same thing on mastodon, kbin, blue sky, etc.
It's been long since I deleted my reddit account, but I occasionally still open up subs that matter to me, like my local city subreddit, and a few other niche places, despite not being logged in. Why? Because that's about the only place I can find them.