My opinion is: Why?
They tried this before... didn't work.
The CA electrical generation cannot even handle a HOT DAY. Seriously, they where doing rolling blackouts when it was 120 in the San Fernando Valley a few weeks ago!!! One of the prime reason was an over dependence on solar and wind, which, shockingly don't produce as much in the evening (the blackouts where in the evening). I mean, who could have possibly predicted that! Hey, just buy dirty power from out of state...
Setting up the infrastructure to support all the charging (charging point and generation) is going to be stupid expensive. Did I mention CA is letting the license on the only remaining nuke plant (Diablo Canyon, which represents a surprising large percentage of the states power) in CA expire in a few years. Oh, and there is a mandate to go carbon free also, so.... all the natural gas plants need to go also! Yeah....
There are nearly 200 utility-scale natural gas–fired power plants in California; together, they provide approximately 39 gigawatts of generation capacity to the grid
You might ask: what about night time? You know, that thing that happens about half the time (and it's generally not very windy)? How do they deal with that? HUGE batteries. Can you imagine how expensive a battery plant big enough to supply power to the entire state would cost?
Did I mention, as with many other states, CA is currently racking up HUGE debt because of COVID?
Besides the grid issue, what's the point? If you can make electric cars that people want to buy, do it. Forcing them to buy them....
Hey, I think electric is cool. Love to see the advancements, but I don't see any point in REQUIRING it... well... other than making things even more expensive in CA....
As with most thing coming out of politicians mouths though, this is more about what make the person saying it look good than what is good for the state. Our last governor liked trains.... we now have a multi billion dollar high speed train being build that is not high speed, and with travel between two small towns... that may be shut down (hopefully) by the massive miss management and corruption involved. Projected to cost 60 billion to span the state (LA to SF), is now pushing 80 billion to go from Fresno to San Jose (which almost certainly is never going to happen).
In summary: electric cars? Yes. Renewable energy? Yes. Mandate 100% of either? That's just stupid!