My memory of my parents cars in the '60's was that 65K miles was about the shelf life, before it became a garage renter.
@catfish1957 I suspect most of that was due to the oil people used in the "then new" cars and trucks. Some people just won't ask or listen if you try to tell them,and would use absolute crap like the old Quaker State 30 wt NON-DETERGENT oil in the newer cars with hydraulic lifters. I remember removing the valve covers from a 66 283 Chevrolet when I was a kid working in a gas station to adjust the valves to quiet them down and remove the miss,and when I took them off I literally couldn't even see them for all the caked on "gunk".
On the other hand,my father,who was NOT known to adopt to new ideas quickly,for some reason didn't use anything but Mobile "Gold" high detergent in the new pink and white 55 Ford Victoria he bought new,and that car had 225 thousand miles on it when he traded it in because he needed a truck. Yeah,it was burning a little bit of oil,but nothing to worry about.
In that 225,000 miles ALL he did to it was change the oil and filter every 3,000 miles,and replace 1 water pump,plus plugs and points when needed.
The same with the Ford pu he bought to replace the Vicky and the next Ford pu he bought to replace the first one. The second one started getting a little shakey after around 125,000 miles because his mind was getting shaky then,and he started swearing "You should get 100,000 miles out of a tune up and oil change." He wouldn't listen to any argument about it,either.
I kept him going by getting a spare set of keys cut,and waiting until he parked his truck by the dock while he was out fishing over his nets,and then slipping up there and changing the oil and filter,and plugs and points for him. Never did tell him I was doing that,despite him telling me I was foolish to keep changing the oil and filter in my car so often,as well as the plugs and points.
My mother knew what I was doing,but she never whispered a word about it,either. She knew he was hardheaded before I even came into the world,so it didn't surprise her at all.
I have no idea why I started doing that. When I was a kid growing up I used to keep asking him to teach me what he was doing when he was working on his car,sharpening his tools,etc,etc,etc,and he kept refusing by telling me "You are too stupid to learn,so go away!" I would normally rub it in people's faces in circumstances like this,but AFAIK,he went to his grave thinking his trucks just kept running good and never needed tuneups or oil changes.