I feel like there's two possible scenarios with BlueSky:
Scenario 1: BlueSky fails and collapses, just like literally every other attempt at creating a direct competitor to a popular social media service.
Scenario 2: Enough people migrate over to BlueSky that it's able to sustain itself as a left-wing echo chamber, while Xitter correspondingly becomes a right-wing echo chamber.
I'd say Scenario 1 is by far the more likely of the two. Literally the only thing BlueSky has going for it is that lefties and degenerates, left bereft of their hugbox, want to create a new one somewhere else, which is what's feeding the current trend. But I'd say the vast majority of people just don't give enough of a shit, so even if a bunch of big accounts up sticks, they'll come crawling back when they realize that the vast majority of their followers haven't come with them, and the only thing these people care about more than ideological purity is clout.