Is there a tipping point where it’s a net loss? If I understand the protocols correctly, the whole back end federation part of the equation is push based, so if everyone was running their own instance, lemmy.ml would have to push every post to every individual instance in the network. At some point isn’t it more efficient to only have to serve posts when people come here to look at them?

You have to make a new account unfortunately.

Lemmy is just the latest in a very long line of potential reddit successors. Historically, you can’t move a subreddit to a different platform because redditors are users of reddit, not users of your particular subreddit.

I would argue that “viewable from” is a far cry from truly federated. The fact that I have to subscribe to infinitely many individual communities to see all, say, “Technology” content across all of lemmy seems like a near-fatal flaw to me.