The law actually doesn't prohibit the NCAA from enforcing its bylaws. It just prohibits the California member schools from enforcing the NCAA bylaws. The NCAA could declare all California schools ineligible for postseason play as long as those schools don't enforce NCAA bylaws, or kick the California schools out of the NCAA altogether. The NCAA could also refuse to have any tournament games in the state of California. The Ohio State AD has already said they won't schedule any California schools in the future in any sports. ****, the Pac-12 and Mountain West could kick all the California schools out of their conferences.
I don't think it's going to come to any of that, but it'll be interesting to see how this plays out.