The person on the left is carrying bags, the one in orange is a delivery driver and a couple of people are wearing backpacks. Aside from car brained, Damaris is also blind.
Montrealer here. When roads are unplowed, cars also struggle. When it’s too cold, cars also struggle.
I live at the top of a gentle slope and as soon as it starts snowing, cars are slipping and sliding down the slope. There’s even a famous video of exactly this kind of thing, with cars, buses, police and snow plows just sliding down the slope.
Cars need very well maintained roads to work in winter. Those roads can also be used by bikes. And if you plow bike paths and bike lanes, just like we do for cars, cycling in winter is usually no big deal. Sometimes while cars are slipping down I can observe cyclists being able to climb the same slope. Or they just push the bike up on foot and continue on their way.
I use my bike in winter and can assure you that it is working.
Addendum: I am a simple man. When is starts snowing I just sit by my window and watch cars struggle to go uphill. In fact, I record it.
Also, just to continue on your points. It’s not -30C every day and snow here is usually plowed within a few hours, AND removed within a few days. Extreme weather is extreme, and one should avoid driving in during heavy snowfall anyway. So either you’re on a bike, or in a car that you must dig out of a snow bank, or using public transit, if the weather is extreme, everyone is going to have a less than perfect day.