In 1975, they built things to be serviceable because they expected regular maintenance. Obviously if you neglect the maintenance you are going to have severe problems, but many people just didn't care about maintenance and drove them into the ground.

Now, they design for a certain lifetime without maintanence, after which it becomes prohibitively difficult/expensive or impossible to repair. This increases the perception of reliability especially given a population who won't do periodic maintenance.

If you look at the "survivor" vehicles that are old and ultra-high mileage, one thing that stands out is the owner(s) adhered strictly to the manufacturer's specified maintenance intervals.