It's worth mentioning that X's problems with toxicity are greatly enhanced by its current leadership, so even if everybody switched to bsky tomorrow it would be different. There are far better tools for users to manage their own experience on bsky than X allows.

But, assume that bsky does turn to shit too... if nothing else the (successful?) migration from X shows that people are capable of moving - should bsky face its own calamity the friction to move again will be lower.

There's reason to hope that it won't end in total disaster though. It should (at some point) be possible to federate with bsky in a meaningful way, and perhaps a migration can be even easier than this one (i.e. you can switch to another instance that is run differently).