The timeline is just crazy, but from a financial stance it makes sense to leave the more expensive location, if you already have the space else where (ignoring that they didn't pay their rent in San Francisco anyway).

I can understand why most wouldn't want to work at Twitter, sorry X, but if you're young with few obligations, I can see people doing it just for the experience of it, at least for a year or two. It has to be an insane ride to be on.