My unpopular opinion is that we should federate with threads. "Embrace extend extinguish" would depend on existing fediverse users migrating to threads. Quite frankly, I don't see that happening. In fact, if there's no federation, there's more incentive to use threads to have a presence.

Embrace extend extinguish, if done on the fediverse, may cause an uptick in signups on other instances, and when extinguished, a portion of those users would leave.

With the Google Chat / XMPP thing, people were using Google Chat, had xmpp support, it was cool, then google pulled the rug so users seemingly dropped.

I don't think Meta has enough goodwill at all to even convince it's own users to return to it's platforms these days. I think Bluesky is more of a risk as it claims to be decentralised to rope people in, but isn't.