Earlier quoted context omitted.
You don’t own your followers. When you move they get a notification you moved and their following lists are adjusted accordingly.
Not when the instance you are on is banned or otherwise disappears and you use your exported data to "revive" your account on a different instance (with a different handle), which is the scenario I proposed above.
I still blog on a server I rent but the backup is hosted in a server in my closet. I’m fully aware that rental can go away any time. And that’s been the case for decades.
Maybe it’s a generational thing but it appears people assume these platforms owe them something. The TOS makes it clear they owe them very little. So you can be muted, banned or deleted at any moment.
I’ve watched many social networks disappear and end up in the footnotes of a Wikipedia article. Nothing about the internet is guaranteed nor permanent. Twitter nor Mastodon owe you anything.