And quite a few of them have will have unplanned trips to do from very sparsely distributed locations (also known as "houses in the countryside") to other very sparsely distributed locations (aka "their doctor" or "their family").
Also, car loan is perfectly suitable for planned, long distance trips with lots of cargo, which unfortunately happen at the same time for everyone (they're also known as "vacations"). I would not want to be Hertz on the 15th of August in a world without personal cars - unless you ban people from traveling cross country to see their family twice a year, which might be required.
I used to bet on "small scale on demand public transportation", but it requires either "communities paying drivers" or "engineers solving self-driving in rural roads", none of which is happening anytime soon.
In the meantime, though, we have to invest in trains, bike lanes, and downsize cars at the same time as electrifying them.
But yes, of course children need a different kind of transportation.
Though, arguably, it's easier to pedal with your toddler on your back than with your grandma !
What's the typical age limit ?
Moreover, it’s also just convenient to be able to get across town in half the time that you can by public transit.
And real humans can occasionally rent a car. Maybe it is not worth holding thousands of dollars' worth of rusting metal for that occasional odd job.
As for snow and ice, Oulu, Finland is an example of how infrastructure defines the way people live:
https://www.youtube.com/watch?v=Uhx-26GfCBU