A few sorta-random thoughts on this, noting that different areas will have different things going on:
Back in the day (say, 3-4 decades ago) only "car nuts" washed their cars at home, everybody else ran them through car washes. Once those came out in the late 50s/early 60s people around here quit washing their own cars overnight.
Back then, it was pretty uncommon for people to take decent cosmetic care of their cars beyond washing. When I was a kid there were very few people using stuff like the Meg's Mirror Glaze line or other decent detailing products and the people who did use them were considered a little odd. Perhaps it was because the stuff wasn't too easy to use (my mother never got over how tough Simonize was back pre-WWII).
By the late '60s people started doing more, and by the mid-'70s it wasn't uncommon for people to at least use cleaner-waxes.
People *who could afford to* used to replace their cars pretty frequently, sometimes every year. My parents were considered unusually frugal because they'd keep theirs for a few years while my friends' parents traded much more frequently. Families would sometimes keep an older car, but it was a spare, not something they drove very often. It was an adventure (in the '60s) when my friend's mom would get out her "old" car to drive us to school- it was maybe 20 years old; now days nobody thinks my '85 Jag is very old.
Once cars quit rusting out or developing mechanical problems (think early emissions controls), people started keeping them longer. The change away from big styling updates made it less obvious that a car was a few years old.
Now, with 2-4 year leases becoming so common, the pendulum seems to be swinging back towards frequent replacement again. But then somebody buys those used, off-lease vehicles and sometimes they keep them a long time.
Now normal people have cars with >100K miles on them, that used to be unheard of...only a mechanic would have such a "worn out" car.
IMO most of the cars on the road here in Ohio look a *LOT* better than most cars used to look. As mentioned, within a couple of years most cars used to be rust buckets with oxidized paint.
These days a lot of people are doing a lot of stuff, and I suppose that keeping their "transportation device" looking "like a showcar" just isn't a priority.
If somebody want to neglect their car, ah...no problem for me. Better than neglecting their spouse, or their kids, or their dog :nixweiss
