SpaceX and Tesla leaving CA are bigger loses, but they haven't left yet, and it's unclear he'll move them, other than opening up more plants elsewhere. Boca Chica/Austin might eventually become the new locus of new hiring for example, but the Dragon/Falcon business might remain in CA for example.

HP leaving is basically a zombie company leaving on life support, it would be like IBM or Kodak leaving.

The real power of the Bay Area is the startup economy, and I think it will be hard to dislodge that, just like it's hard to dislodge Shenzhen, because of the "nexus" effect, or chicken and egg as you mentioned. If all of your customers and workers, and supply chain, and investors are in one spot, as an entrepreneur, you're going to gravitate there, even if the costs are high.

I mean, you get can Silicon Hills, and Silicon Alleys elsewhere, but I don't think they'll overtake the Bay Area.

However, I could see Texas, Arizona, Nevada, becoming the "Mars Plateau" in the future. Realistically, Musk needs a coastal port for logistics, ability to mine resources, and a state that would be complicit in dealing with angry laborers or neighbors who don't like Sonic Booms going off all the time.

CA's just not going to let him run as roughshod as he wants, e.g. the worker safety and labor issues at his plants, the environmental impacts of what he's doing in Boca Chica, etc. That slows down his time schedule a lot, I don't blame him, he wants to get to Mars quick, but then again, if I were living near a Starship test area, I'd also be annoyed by all of the traffic, tourists, and explosions, so I don't object to him trying to get as far away from regulated residential areas as possible.