Well, unless they can figger out why Teslas are spontaneously combusting and until they upgrade their outdated power grid and and cover about 1/2 the state with solar panels and wind farms, there won't be enough electromotricity to charge all the electric cars. I guess Californians will be getting around on surfboards and hemp-sleds. Horses will be an option, but I'm sure they'll ban methane by then too, so the horses will all become dogfood.
California (and Arizona) should build solar "farms" - there's 100s of thousands of empty land that is parched and baked by the sun...given all the electricity used for air conditioning in So Cal / AZ / NV it would make sense vs. trying to ship electricity from Canada over a choke point in the transmission lines.
CA has a very antiquated and undersized electrical grid - brown outs are always a possibility.
Another point is Mexico contributes a lot of pollution that comes up from San Diego, up the valley into LA Basin.
30+ years ago you didn't see pollution in San Diego - and that was with 70s / early 80s emissions controls.
I've seen LA's air get less polluted compared to nearly 40 years ago when I first visited the area (you could see the hills around LA)
San Diego has very clear air back then. With the increased manufacturing across the border in Mexico, air quality has become worse, despite the lower emissions from Diesel heavy trucks (ULSD fuel & DEF) and modern emissions on passenger cars...all the while the population of vehicles has increased over the decades there.
I just can't see this happening by passing a piece of legislation to affect the entire state. Some regions need more attention that others. Even if it did...it would be 40 years of run-off of existing vehicles on the road to be out of service.
I recall London, GB proposed banning ICE vehicles from being sold in future years as a proposal, but that's pretty far fetched.