Just took a Waymo ride across San Francisco 3 nights ago in hard rain, at night. A hilly complex city with bike lanes, kinda oddball medians and bollards, many pedestrians, and homeless people wandering down the middle of streets. It did great.
Even if it didn't work in snow (and it's unlikely to do worse than humans), all the west coast, desert west, and south have basically zero snow all year long.
How else would you do it? First, get the technology to work at all before doing the harder things it can't handle yet. Crawl, walk, then run. Or in this case, drive in snow. Even if it never gets there in my lifetime (which I doubt), it's already working.
I don’t know where this idea that driving in SF is easy mode comes from. No one who has actually driven in SF would say that. Yes it doesn’t have snow, but it has rain, zero-visibility fog, lots of pedestrians and cyclists, heavy traffic, narrow roads, steep grades, bus-only lanes, lots of cars parked on the street and double parked. Self-driving companies don’t pick SF because it’s easy, they pick it because it’s the most challenging city that’s close to their engineers.
Even if it didn't work in snow (and it's unlikely to do worse than humans), all the west coast, desert west, and south have basically zero snow all year long.