yes you do. There is a whole lot of driving that happens in perfect conditions.

Think "Truck driving, on long highways".

Replacing half of all truck drivers is still a trillion dollar industry.

And for your robo taxi situation, you can simply only allow the robotaxis to run half of the time.

Human drivers, can simply get in their cars, and be paid to drive, when it is likely to be unsafe driving conditions. IE, surge driving/pricing.

But there absolutely would be days/times/places where the robo taxi would be perfectly safe. And these days/times/places could be predicted easily, ahead of time.

IE, in arizona, I am sure that it is safe most of the time, and there would not be any issues with snow.