In the late 70's US auto makers continued making gas guzzling beasts... they also were of poorer quality than their Japanese counterparts. Talking about CARS here, the trucks in the US were superior to Japanese back then. (and still maintain an edge today)
That's the conventional wisdom, fueled by magazines like CR. But as a former self-taught auto mechanic (I made money in high school and college fixing cars) I worked on Toyotas, Datsuns, Fords and Chevys, and I saw the difference in quality first hand.
The sheet metal on the Japanese cars wasn't as heavy and more susceptible to paint damage and rust. The unit body structure was the same way, plus you could buy a comparable American brand that was body-on-frame, or unit-body and much heavier. In a moderate accident the US branded vehicle would drive away while the Japanese vehicle would be totaled.
The interiors of the Japanese cars were deplorable. Almost all Toyotas of the era required a right-handed driving technique due to the windshield visor not able to hold its own weight. Knobs would break off, seats wouldn't adjust, vinyl would crumble. I specifically remember my friend's brand new Maxima with the machined aluminum trim covering the center console- it was literally half the thickness (gauge) of a typical beer can.
You're assessment of the trucks is correct. Since all manufacturer's share corporate philosophy, managers, designers, raw materials, vendors, factories, and many parts between cars and light truck lines, any reasonable person would realize that the relative quality of a manufacturer's cars and trucks is going to be about the same.