I currently follow 447 people on Mastodon, and 258 follow me. I think on Twitter, after 15 years of having an account, I followed about 1000 people, many inactive by the time I tired of Naughty Old Mr Car’s antics, and was followed by about 1000 (presumably ditto). _In my niche_, it’s a perfectly adequate replacement, and is better than old-Twitter in some ways (it is so much better than the post-Musk mess it’s not even funny), but it would not be for everyone. I post about as much, maybe a little more (it’s easier to have a conversation, for a variety of mechanical reasons.)
I do miss quote-tweets as a mechanic; while they could certainly be abused, there were legitimate use cases. Mastodon plans to add them, but AIUI getting the appropriate changes made to ActivityPub to allow for consent-based quote-posting is a whole thing.