[Ferkv]

> if they had just proxied cached versions of the most popular instances through a single larger server.

I mean, isn't any instance in the federation already offering a proxied cache of the content of all other instances you access through it?

You can just register/login in mastodon.social website the same way you can register/login in Twitter, and then access cached copies of content from the entire fediverse compatible with Mastodon.

If you are gonna make new accounts connect through a global mainstream proxy, you might as well just let them connect through a global mainstream instance. I personally do not see the problem with one instance being more mainstream than the rest as long as federation is still respected. It's definitelly still an improvement over centralization and if it ever becomes a burden it'd be easier to migrate.