The public at large doesn't care about any of that at all. I don't think mastodon will ever grow that large due to how painful the signup process is. And that's fine! But we have to acknowledge that only a very small portion of people care about things like privacy to the point of uprooting their social media where their friends are.

AT Proto is more interesting than ActivityPub anyway, but I think BlueSky will eventually succeed because the signup is painless. You just sign up on bluesky, there's no need of discussion on which instance, etc. There's no worry about losing everything if the particular instance you're on goes down, or having to deal with migrations.