A company that moved to Texas over 10 years ago had this to say.

"We got an entire building built and done, in the same amount of time it would have taken us to get a sign permitted in Cali"

It is not just the building rents that are expensive in Comifornia.
It is the bureaucracy (that hates businesses)
It is the regulations (that are often meaningless)
It is the lack of workers who want to work.

And, as more businesses leave California, it becomes harder to do business in California.
The support businesses are leaving too.
The suppliers are gone.
Some industries won't even deal with shipping to California anymore.

And then there is the taxes.
California demands you file tax returns for seven years after you left, or they will just take from your bank account what they think you owe.

There will be no middle class left in California if things keep going as they are being pushed now.