Threads doesn’t need to do an EEE attack. They’ve already gained many more users than the entire Fediverse. At this point, I wouldn’t be surprised if they decided to not join the Fediverse at all.
I would never use Threads, but I would use a Mastodon instance that federated with Threads. I already see many journalists and content creators I like trying it out, who either stopped using Mastadon long ago or never even tried it in the first place. If Threads started doing things that negatively affected my experience, I would then switch to a Mastodon instance that wasn’t federated with Threads.
Yeah, mastodon definitely needs a better algorithm. Algorithms can be designed to promote whatever the maker wants. It doesn’t have to be designed to maximize engagement or the specific kind of engagement that tends to promote crazy conspiracy theories or fascist rhetoric. The algorithm could just be simple collaborative filtering with some randomness thrown in to pop “information bubbles,” which would be much better than what they have now.