I'm pretty sure Google, Apple, all the movies studios, HP, Tesla, etc. are not owned by the US in any way. That would kind of violate the entire model of capitalism. And considering a lot of these tech companies make their stuff in China, an independent California would probably have no trouble negotiating trade deals. Plus the port of LA is the largest trade port in terms of dollars in the world. Basically it would be a major loss for the US, but it doesn't really matter because it isn't going to happen. Anyone who wants it is delusional and is too caught up in political rhetoric to recognize basic economics.