My prediction on Twitter vs Threads: Threads will be a much younger demographic and more at the center of pop culture. Twitter will be a slightly older demographic and more at the center of world issues/politics.
Thread
Both will survive due to this substantial platform/audience differentiation.
Which I think leaves Posts to continue its mission for being the more networking/work/LinkedIn platform. Makes perfect sense. (Right now more creative-focused, which works for me 👍)