I understand you may not have lived carefree but here's two places with extreme weather that do fine without cars (provided people invest the minimum amount to establish public transport):

Winter (Norway, way below freezing): https://youtube.com/watch?v=Uhx-26GfCBU

Summer (Taiwan, 36C+): https://www.youtube.com/watch?v=1dBk7lq8o1Y

Ah yes, winter! I live in a wintery place (Quebec) and cars in winter need very much care to work properly. They need plowed and salted streets or they get stuck or can't go uphill. If that level of care was the same for pedestrians and cyclists, it would be much easier to move around without a car.

Also, you may need a car because of chronic pain but surely not everyone driving a car needs one for chronic pain? And wouldn't it be nicer for people that really need a car if there were fewer cars around?

I'm in my early 40ies and lived all those winters without a car and I still think it's silly to say they are "adapted" or "working well" in winter. Every winter there are multi car collisions/pile-ups on highways. They slip and slide easily. Multiple times in a year cars can't climb the little hill in front of my place. It takes even more space to park them as there are snowbanks everywhere. Sometimes they get covered in ice.

I really can't see the appeal of a car in winter.

Good quality public transit can solve those issues as well. We should have a variety of options available for a variety of people who need them.

I think the term "car free" is a misnomer, more like "car as a non primary form of transport for most people most of the time" is more accurate but doesn't roll off the tongue as well.

There are a lot of people with mobility issues in such cities that are serviced in different ways, a lot of times with specially licensed cars etc.

Yeah, I hate the term "car-free". That said, even for someone who primarily uses a car, advocating for bike lanes and public transit makes sense, as the fewer people there are taking up road space and parking, the easier it is for you to drive / park.

Yeah, it gets to 48C in the summer here and biking or walking is not a preferred option unless showering at workplaces becomes a new norm