Trust me, in the 70s and 80s most cars were crap. That includes the Japanese. If you wanted reliable in the 70s and 80s you bought a Mercedes. We had Hondas and Toyotas in the late 70s and early 80s and they weren't that reliable. Cars IN GENERAL are WAY more reliable now. Ask anyone who truly owned an import back then how good it was. It wasn't that good, especially compared to any vehicle today.The current lineup isn't crap, you're right. There are a few crappy cars, (leftover from older lineups, which were mostly crap) like the Uplander, which is a Lumina APV in disguise (but less reliable).
I stand by my opinion though. Through the 70's, 80's, 90's, and very early 2000s most of GMs lineup was garbage. The Japanese and Koreans would not have dominated a large portion of the market had the lineups not been crappy (The Toyota recall-a-thon is a very recent event).
Excessive cost cutting is mostly to blame for this, followed by arrogance.
Don't believe me? Go check JD Powers' ratings for cars over the past 20 years. What is considered "average" now is what was considered "top tier" -- i.e., Lexus/Buick -- now! It's utterly unbelievable.
The problem with GM and the domestics in general was that they didn't improve their cars and seemed to actually take a laissez faire attitude about quality in the late 70s and 80s -- hoping they'd last through warranty, for example. They went down while Toyota and Honda in particular incrementally improved. This incremental improvement over 15 or so years left a huge gap between the domestics and the Japanese.
That incremental improvement ALSO left a gap between Mercedes and the Japanese. It was quite stunning to witness.
Proof, to these old eyes, of the reliability of cars today is seen daily during my commute. I don't see dead cars littering the roads and highways anymore. Two decades ago you couldn't make it into work without finding a half dozen or more cars dead on the side of the road. That's an improvement in quality that's visible and tangible.