The big ISPs that could get away with shifting the status quo have some presence in California, and most of the big tech companies that you'd want to convince to pay you to prioritize their traffic are in California. Not to mention the fact that it can be difficult to tell if your customer is in California: what if their cellphone is connecting to a Nevada cell tower, but is actually in CA, and thus protected by law? What if the customer is using a VPN?

It's messy enough that, given the pretty limited upside, I can see why companies would be hesitant to try and work around it.