I suspect a part of Elon's issue is pure ideology. However, I am a railfan (I even ride long-distance Amtrak for fun) and a Texan advocate of building HSR from Dallas to Houston, and I have to say he at least has a point about California specifically. A French contractor involved in that project famously pulled out saying that North Africa was far less politically dysfunctional.

https://www.businessinsider.com/french-california-high-speed...