i listened to a conversation today where 4 or 5 people bemoaned the fact that they couldn't do the routine maintenance on their cars anymore, like they did in the 70s.
it was only towards the end of the talk one of them realized that cars last twice as long now as they did then.
(anecdotal!)[/QUOTE
Two things factor more than any others to bring this about, in my opinion.
Fuel injection. No more maladjusted carburators dumping gallons of raw gasoline into the engine.
High gear-overdrive transmissions. The less revs, the less wear.
I have gotten over 180,000 miles out of 1962 technology, but it is hard to do.(a six cylinder Chevy Biscayne with a 230 CI six banger and a two speed powerglide, 4.10 gears)