What, Bluesky shouldn't be let into the fediverse, or Bluesky shouldn't let Threads in?
I don't see any problem with Bluesky. They've got a decent philosophy and approach, tbh.
Sure, for people who pay attention and / or care. But sadly I think the real comparison with be:
Ease to get started:
Mastodon - Learn what a server is, find a server, create an account.
Threads - Just download it. You probably already have an account without realising.
It's going to do well.
Sure, it's mostly going to be celebs, brands and 'content creators' but that'll still mean a lot of people. And folks will go where the people are.
Personally, I'm hoping BlueSky just dish out 10 invites per user and bring in people to that infrastructure. It looks like a good middle ground between fediverse and simple Twitter experience.