If Meta had put Threads on the AT protocol instead of ActivityPub, things could have been so different... maybe there's still time. The engineering philosophy for AT / Bluesky is incredible, being able to develop your own timeline algorithms, distributed moderation agencies, etc. But whenever I give Bluesky a try unfortunately I just can't find people talking about my interests. This seems like a scale problem, which Threads solves.
Nothing is stopping you from building your own AP algorithm either though, right? An "algorithm" is, ultimately, a ranking model that ranks a set of incoming posts based on some criteria no? Nothing stops someone from building their own ranking model for themselves.
I agree that the Bluesky userbase doesn't really talk about the topics I care about and I think the audience is a big factor.
Anything on AP or AT can bridge both ways anyway
Meta's ActivityPub is very fake, it's not only off by default and functionally limited, but also has a dark pattern to get you turn it off.
It would be the same if they do ATP.