The way Mastodon is broken up into little communities such that it’s hard for anything to go viral and you can’t easily search for everything being said about a topic kills a lot of the value of old-twitter. Comes from Mastodon having been created as a twitter alternative with a different philosophy back in the old twitter days, while bluesky is more a reaction to Musk twitter used by people who didn’t have a problem with the old version.
The platform is the users but it’s also the owners. Twitter got a lot worse when Musk took over and started turning it into a Nazi propaganda platform even though the userbase didn’t immediately change.