I heard a story on NPR today about new cars and how much better they are than older cars were. That may be true in a lot of cases, particularly for certain makes and models, but it's my opinion that oils and lubricants have gotten so much better and deserve much of the credit.
It used to be that you could expect a car to last 100,000 miles if you took good care of it. Now, today, most would expect a modern car to last 200,000 if it's taken care of. I have noticed that older cars with good engine designs can also achieve that kind of mileage, even with their old designs. Take Chevrolet V-8's -small and big blocks. Rebuilt motors from the 70's and 80's lasting another 200,000 miles. Chrysler Slant 6's and chevy 250 straight 6's lasting several hundred thousand miles- original motors.
Anyway, I think it's the oils more than the engines.