Imagine how long Americans would be able to keep cars with low maintenance costs as well if there were no government mandates on fleet mileage, no mandates for ethanol, no restrictions on engine size or fuel type?
If a car could be built simply as a means of transport, with no government interference, I would bet cars could be built that would easily last 400K miles.
They could be built to last a million miles if long life were the only consideration. I remember when “car trouble” almost always meant engine trouble, now the engines will last on and on if serviced properly but all kinds of other things go wrong. I have had two intake manifolds which were made of plastic split on the road and pour water out necessitating a tow and an expensive repair. I didn’t know what transmission trouble was until I bought a 1980 Pontiac Pheonix and I have had some kind of transmission trouble with everything I have owned since except for a Dodge van I bought used and an E-350 Ford van that I bought used. I have had to replace heater cores on three or four vehicles, that was unheard of back in the fifties. I have had to replace the cooling fan assembly twice on the same vehicle because the control module goes out. I now work part time at a big car auction just to make some pocket change and get away from the house and I see all kinds of goofy problems on vehicles with less than fifty thousand miles on them. All kinds of electrical troubles, it would take too long to list them.