The Chevrolet Suburban was quite possibly the first SUV, and do you know how they built it way back in the 1930s when it first came out? With a "stationwagon body on a truck frame", just like what you're describing. It was built that way for reasons entirely unrelated to what you're describing here.
The reasons SUVs became popular in the '90s and 2000s is because the big three American manufacturers were, for various reasons, no longer competitive with the Asian manufacturers in the small cars market. Because the margins were either negligible or negative for small cars, they decided to refocus their efforts elsewhere, and SUVs made a good deal of sense, since their margins there were significantly higher.
Also, you're rewriting history a bit. Sociologists actually study the whole SUV phenomenon, since Americans largely didn't want big cars before SUVs became popular. A huge amount of marketing went into convincing people that these bigger cars were more protective than the smaller Asian cars, gave you a better view of the road, and were generally just safer to drive, leading to a massive change in the public's perception of large cars. It may be hard to remember now, but when SUVs were first getting pushed on consumers in the '90s, they were perceived for quite awhile as being utterly ridiculous. It took a few years (and the realization that they were a "cooler" alternative to the minivan) before they were widely accepted or even viewed as being desirable.