> They suffered and died.
They were (mostly) taken care of by extended multi-generational households. They obviously died and/or suffered to the extent that medical and QoL technology was insufficient. The whole status quo of pensioners migrating to Florida-style retirement community necropolis with a F-150 and a rubber stamped driver license is a modern US-centric phenomenon.
You are naming disparate & absurd things as the reason that European like walkable communities are bad for old people, like the difficulties of 1930's cities (or perhaps pre-industrial, you aren't very clear), the difference in landmass between the US and Europe (?) and the fact that there is a small range of disabilities that allow someone to drive and shop to Costco but not to go to a cornershop.
The reality is that being old sucks ass, but being old and sedentary (when you can avoid it) sucks worse. I've taken care of multiple senior family members & friends, the ones that were active, i.e walking everywhere, not avoiding stairs completely, have lived longer and happier. Sure, even active people gradually lose the ability to do day-to-day stuff and cars or microcars[1] can help them and other people with mobility concerns, but that's not an argument against walkable places.
Making streets non-hostile to pedestrians, having necessities closer to residences and prioritizing public transport makes people stop preferring cars as medium of transport if they don't need it (youngsters). This actually helps with traffic and in turn helps the people that need cars like someone with a rolling walker and arthritis or a delivery van.
Implying that people advocating for walkability are heartless youngins that don't care about old people just because you are losing arguments left and right, is actually really unempathetic.
[1] https://www.youtube.com/watch?v=B9ly7JjqEb0&t=224s