Why hasn’t this gone to the Supreme Court?
To get to the Supreme Court the unconstitutional law must be passed.
Then it must be enforced on a real person or entity.
Then they must fight in in court.
Then it needs to work its way through the appeals process if the appeal loses in lower court.
Then the Supreme Court needs to agree to hear the case.
All of this takes a lot of time.
As cgbg noted in post #8, it takes a long time for a problem to wind its way to the US Supreme Court. But maybe a district federal judge could quickly strike down this (proposed) California law.