What the cost of owning a car is is so much dependent on the vagueries of the tax system, insurance etc that it is difficult to comment unless you live in that particular country or county.

No one solution would fit everyone, and alternatives vary.
I don't think it is realistic to look at the worst of every situation - sooner or later you have to start working out what compromises you can make, and making the best of things.
For instance, you comment that it gets too hot in the summer to ride a bike in some regions.
Well, most people go to work in the morning, and come home in the evening, when the sun is not at it's peak, and an electric bike would mean that you would not need to pedal and get sweaty.

If that is where you live, if a car ride can't be afforded, you just have to figure out something - perhaps car pooling.
Alternatively it might be necessary to take digs during the week close to your place of work.

Or you might have to somehow get the money for a full EV, and perhaps make people pay for lifts.

In any case, where it is essential present standards of comfort and convenience can certainly be compromised.

I have a 21 year old farm truck that I bought used 10 years ago. It stays outside under no cover 12 months a year in the Mid-Atlantic region of the US. While I only use it ~500 miles/yr, it runs like a top with little to no rust and I expect to be using it for another 5+ years. It especially comes in handy during snow storms, so it sees more than its share of salt.

Exactly - just plowing is not enough. Without proper de-icing - i.e., usually, road salt - which is getting to be a serious issue in some Wisconsin cities, it's unsafe, without the protection of a car, to be anywhere near cars that may cut loose and slide at any random moment. And the unsafe zone can readily include the sidewalk.

In Madison (the capital) city policy is not to plow unless there is a large snow, and not to de-ice except on major streets. No doubt this is more congenial to the slimy vermin infesting the lakes, but it does make it extremely hazardous even to walk. Not only are there the sliding cars, but one simply cannot get very far without needing to try to walk cross the slick sheet of glare ice that, in winter, passes for a street. Studded tires even on a normal bicycle do work under some conditions, but they don't solve the problem of the sliding cars.

the vast majority of people could easily bike 20 or 30 miles a day and find new joy in life.

I have no doubt that such will be the case, and obesity, heart disease, hypertension, etc will lessen from the exercise.

Treehuger had an article: It's More Dangerous NOT to ride a bike. The nickel tour is that while you may be at greater risk of accidents on a bike, the health benefits of pedaling outweigh the accident risk by 4 to 1.

I find it hard to believe that a weatherproof battery container is a technological impossibility.

I was biking 14 miles to work last December, which was a bit much, but I don't see how 3 miles would be much of a challenge.

I keep my lithium ion batteries dry so I can ride 365 days a year in Chicago regardless of the weather.

I stopped driving because I don't need to. I've built a bike that can go 45 mph, a bike that can go 200 miles on a charge and a bike that can pull 1000 lbs of cargo on a homebuilt trailer. There are plenty of ways for us to move forward and prosper in a low energy world.

At least in this part of Ohio, the sidewalk snowplow takes a lot longer to show up than the road snowplow, and three miles is further than the sidewalk snowplow goes in most directions. Once the deep snow hits, it really is much easier to get around by bike than walking, even for things that are within walking distance for most of the year.

If the snow is a mere one foot deep, what conceivable obstacle would that be for cycling? Its not like anyone in their right mind would use a "road" bike for commuting on the actual roads in Northeast Ohio. The snow slows you down a bit, but for short distances, its just a matter of allowing five extra minutes.