I wonder that too. ActivityPub/ActivityStreams seems really interesting, but I haven’t found a good roll-up of (1) the problems it was designed to solve and (2) the design philosophy of this solution. Once I understand what’s possible vs. what Mastodon’s implementation of ActivityPub can do, I hope to be able to answer the question: Can an alternate implementation be less of a nightmare to scale, or is that intrinsic to the protocol?