A lot of people use social media to follow celebrities, brands, politicians, etc., and Mastodon doesn’t have that (yet at least).
I prefer Mastodon, my feed consists of the people I decided to follow, instead of an algorithmic one. But one have to accept that Mastodon lacks the kind of users that most people want to follow.
Hopefully, if Meta ends up delivering on their promise to add support for the Fediverse, I will be able to follow the kind of people that otherwise would’ve never joined Mastodon (ie brands that would offer support for their products), from my Mastodon client of choice.
I know a lot of people disagree with Meta joining the Fediverse, but I prefer to be optimistic about it. Also, Mastodon supports blocking domains at a user level, so if you really don’t want to interact with @threads.net users, you can do it yourself.
Worst case scenario, we get back to the current status quo, so there’s nothing to lose.
That's pretty much why I've been reluctant to join either Mastodon or Threads, compared to Lemmy. On Reddit/Lemmy, it doesn't really matter who I talk with, as long as a community exists for the topics I'm interested in. But on Twitter, I pretty much exclusively follow content creators and don't care to interact with anyone else. Until those streamers/youtubers/artists jump ship, I'm pretty much stuck on Twitter with them. When they do, I can only hope they pick Mastodon over Threads, so I can actually filter my feed to those I choose to follow, but ultimately I gotta go where they are.