Don't panic!
CARB does these studies from time to time and each time they find that collector cars contribute so little to pollution in the state that no action is necessary. This is totally separate from having emission free zones in cities.
They are actually planning to roll back the biennial emissions testing for older vehicles. Currently vehicles that are 1975 and older are not subject to the smog testing. That will change to a newer year. At one point it was supposed to automatically change each year.
The difference this year with the CARB study is that social media has turned this into a freak out session through the classic car community, encouraging owners not to respond to the study. They know how many classic cars are registered in the state, if you don't tell them how many miles you drive them, they can, and will, assume that you are driving them more than you are.
Nick