I'm not sure I even follow this argument. I can stand up a single host in an hour or two. Six months from now, there will probably be 30 competing providers who can do it at the push of a button. Respectfully: why is it relevant to me what Mastodon was "made for"? I just want to follow people and post stuff. That works just fine even if literally everyone has to run their own server.

ActivityPub is like RSS and Google Reader rolled up in Twitter's UX. That's what I'm psyched for, and the part of it that I think will catch on.