The one thing I've learned from people is that instead of leaving Twitter, they will make new alts to evade bans (see Groypers and "find my frens" becoming a minor meme, Nick Monroe and his endless alt accounts until he gets jannied for ban evasion, etc.) because they see Twitter as ground zero for public discourse, a ticket to fame, etc.
The only people who go to fedi have to take the initiative, be in the right mindset, and not think it's just like Twitter, because it's not like Twitter.