While California will not exit the USA, it would be a good think for the rest of the USA if it did. The Dems would lose 55 electoral votes sparing the rest of us from another Clinton or Obama who run as centrists but are really far leftists.
California will crash and burn as a separate nation and will be forced to seek reentry into the USA. If the members of Congress are smart at that time (Yeah, I know!) they will insist on creating the California Territory and have it run by a territorial government for at least twenty years. At the end of the twenty year period, the California Territory will be slowly divided into smaller states allowing the more conservative parts of the territory to enter the Union first and the most liberal parts of the territory later. Of the five states admitted, two with a bit over half the population would contain most of the liberals. The other three will contain the conservative part of the territory. The Democrats will get a lock on about 30 electoral votes. The Republicans will get a lock on about 65 electoral votes.
If the people of California refused to become a territory upon reentry, let them join Mexico as California Norte.
California has one of the most educated and advanced workforce in the world. It’s GDP is 9th in the world. If Portugal can be a country then California could certainly be one. The arguments against this are getting ridiculous.
If they are willing to take genuine action in using the truly available natural resources, then they would succeed. However, I don’t see them as really willing to secede, because they would rather take the easier route of relying on the other states for their resources.