Even if the dev community around BlueSky/AT Protocol grows and there are lots of clients, I can’t get past the fact that it basically uses a slightly modified version of Fediverse instances.
That means the same problems will exist involving centralization of user base around a few overloaded instances, and the whole “instance administrator acts as a feudal lord” and “instance can’t afford to operate at this scale” issues.
Even if it’s easy to migrate between instances, the vast majority of casual users just aren’t going to think to do that.
Nostr’s model of not tying identity/content to a single instance is a critical advantage there.