The biggest step forward, was when manufacturers stared making low friction engines. Oil suddenly improved in leaps and bounds, and cars started passing 100k, with no noticable wear.
200k, is quite normal, on many cars, these days. I had a Merc, with 364k on it, and was ripe for clocking [as many do end up], as it drove mint. You would of thought it had done, around 75k.
Nearly every week, I would see BMW 5 and 7 series, heading over 200k, with absolute no engine wear. Its owner care, at end of day. To call a car with 80k, high mileage, these days, is daft, as its just getting nicely run in!
In Spain, mileage is unimportant. Lots and lots of different makes, have 300k+ on them, and as long as they go, and pass the test each year, miles will just go, up and up.
In New York, is an old Checker Yellow Cab, run by a woman for 40+ yrs, and its done over 5 million miles! Good old lazy V8!!
I have had more problems, with low mileage cars [average 2k a year], then any high miler. Give me a good maintained high miler any day!
Andy