You can drive a car a lot longer than you can walk. I could do a 30 minute walk as a younger person, but now it's something I could only do as a special thing, not every day to a job. Society will not be able to redesign for this; if anything it's other people who own cars that act as caregivers for housebound seniors as their work.
Oh, wow, that's not my experience at all. Most of my older relatives and their friends walked 30m/day into their 80s, long after they no longer had the reflexes or eyesight to be safe drivers.
The thing with walking is that it's very much a "use it or lose it" thing; people who never owned cars are much more likely to keep walking.
Can I ask what age you? You should easily be able to walk 30 min at any age short of 60, unless you have relates health issues. If you can't then you need to seriously consider improving your health.
My dad is 66 and can easily walk for hours. I think the problem here is strictly health issues, not age. (Obviously, health issues often come with age... but age itself is not the limiting factor at all!)
