I just don't think bluesky is going to last, it's vulnerable to the same thing that made everyone jump to it from twitter. They say it's federated but it only kind of is, mostly it's one big instance just like twitter, controlled by one company that seem to have a pretty unclear business model.
One day they're going to realize they need to make money, but they have no real way to. It will then be sold, or be shut down.
Mastodon is a bit less vulnerable to that, being actually decentralized. On the other hand there are the well known reasons people don't care for mastodon and they're all fair.
I just think mastodon has a better chance of lasting than bluesky.