How the fuck has JavaScript lasted three years, let alone 30?

Because it’s easier to constantly improve an existing standard than getting the major players to work together to agree on a new standard.

And also because JS has come a long way. Its runtimes are way faster than they have any right to be, and it’s hacky enough that you can warp it into almost any workflow you want.

Does everyone who’s following the old account automatically refollow you when you do that?

It doesn’t port over any old comments/posts, but I’m pretty sure that when anyone @'s you, it’s forwarded to the new account.

IMO it’d still be useful to be able to use an identity you control, like a domain name.

Mastodon already does this

It’s worth pointing out that while ActivityPub doesn’t currently support account migration (although there are proposals in the works for how to do this), Mastodon does have a weak form of support right now.

You can create a new account on another mastodon instance, then you’re able to point your old account to your new account.