Didn’t people leave it for BlueSky?

A small number of people yes, but most influencers remain on Twitter or use both.

I should also point out that BlueSky is backed by crypto bros and they've never had any intentions of improving anything the way the people who want to move moved things.

They ran on the idea of decentralization but ultimately BlueSky is, in practice, completely centralized and its not possible to decentralize it. You can run your own instance, but that would just be a separate centralized instance as opposed to any sort of meaningful federation.

I can’t figure out how to use BlueSky… could never get Twitter to work either, maybe it’s too Gen Z for my Millenial ass?

I hate to say it but.... that has nothing to do with age, because there are old people on either. Its just a microblog platform like any other microblog platform.