> The difference between what winter-only tires can handle vs winter-rated all-season tires is so minimal that they're not with getting.
Yeah.. no. The difference is night and day.
Put on some Nokian Hakkapeliitta tires and prepare to be amazed. The grip on snow is spectacular.
All the years I lived in snow areas I drove a Miata of all things.. RWD, light, no ABS, no TC, 4" clearance. But with Hakkapeliitta tires I never once had any trouble, while people in their trucks and 4x4s were stuck on the side of the road due to all-season tires. A true snow tire is a whole different level.
> Northern California ... chain controls
The whole California chain thing is brain damage. The proper safe answer to driving in snow is top quality snow tires, not chains. Chains is the worst possible idea. The chain laws are laws created by politicians who live in sunny Sacramento and have never seen snow and have no clue.
A car with Hakkapeliittas (Blizzaks are good too) will outhandle a car with chains 100% of the time.
The difference between two-wheel and all-wheel drive is night and day, compared to the difference between winter and summer tires. Even then, it all goes out the door when conditions get icy and the only option is studs or chains, to get any traction.
Chain controls, and really all winter regulations, like snow load factors in buildings and whatnot, are created locally, not by the state. Most politicians are from Southern California, and all the state cares about is air condition efficiency and water usage, as though everyone lives in the desert.
> The difference between two-wheel and all-wheel drive is night and day, compared to the difference between winter and summer tires.
No, this is incorrect. Just try it.
Summer tires are hopeless in freezing temperatures (and are not rated by the manufacturer to be used in such cold), as they become rock hard. As much grip as plastic kids big wheel tires.
Ultimately, what you need the most, is grip. You could have an 8-wheel drive vehicle but if the tires have no grip it will just spin in place.
In the snow by far the biggest advantage comes from true snow tires (not M+S or all season) due to how much grip they'll provide.
A 4x4 is an additional advantage, of course. A 4x4 on snow tires will do better than a 2-wheel drive with snow tires. But a 2-wheel drive on snow tires is infinitely better than a 4x4 on summer tires because if there is no grip, there's no grip.
If you are driving on pure ice then yes, chains or better yet, studs, are the way to go. That is a very rare scenario.
> Chain controls, and really all winter regulations, like snow load factors in buildings and whatnot, are created locally, not by the state.
No, these are state-wide Caltrans rules.