You're asking "how is a site like Gmail different from a site like Twitter?" If Gmail goes down, you can get a different email address elsewhere and still talk to everyone. If Twitter goes down, you can't get a Twitter handle elsewhere and still talk to everyone. Mastodon is like email.
What drives people to use social media is gathering followers and likes. You will lose those when your provider shuts down or shuts you out. And you cannot get them back.
> What drives people to use social media is gathering followers and likes.
I don't think that's true for all users, and maybe not even most. I'm not even sure that the people for whom it is true are key to other people's desire to use social media.
OTOH, persistence is key to social media where transssctionality is key to email, so losing a social media handle has a bigger impact on a social media user per se than does losing an email addresses to an email user.
