No, it isn't.
In California the support for sports is really weak. When I say winning, I mean winning championships.
The Great Lakes and up-state New York are different.
There is a reason the Bills, Browns, and Lions all draw fans to their games despite being small market teams and not winning.
There is a reason the Chargers left San Diego and the Raiders are leaving Oakland.
This is true of basketball too. If you look at college attendance there isn't one Pac 12 team in the top-30 for attendance. It is mainly Mid-West and Great Lakes.