In the case of Twitter these changes are impacting a much more diverse population of passive consumers and active content creators, and doing so in a way that these policy changes, if permanent, will induce chronic friction in using the platform, so it may be a better opportunity that prior movements to ditch existing platforms.
I’m talking about probabilities though, not predicting that as an outcome. And I think the overall probability, while higher, may still not be too high. But I’m just an interested observer with no particular expertise in the social dynamics of network effects, so take this comment in that context as well.
What's happening now with both Reddit and Twitter is effecting almost all of the users equally, which potentially opens up more of generic migration option. I'd never been that interested in Bluesky before, but in the last couple days, 5-10 people I was still sometimes checking in on on Twitter moved over, so now I can't see their posts at all on either platform since I don't have an account on either. It's a real bummer, and it feels like it's also preventing people from really committing to Bluesky, since there's no even read-only access to it, people who still want to have some reach can't use it exclusively.