A big reason car companies push trucks so much is that they are more profitable per unit. Demand is extremely limited in terms of quantity, because you can only really sell about 1-2 cars per family, per about 10 years.
That means, all else being equal, a car company makes more profit selling a vehicle that has a higher profit margin. The $80k trucks my family members buy do not cost 3X as much to manufacture as say, a nice Camry, but the price you pay is about 3X. This means the dealer/manufacturer just outright make more money if a higher percentage of people buy trucks instead of small cars.
Consumers have "signaled" that they will be fine paying three times as much for the same exact feature set (no, they are not hauling anything, and there certainly isn't a massively higher percentage of Americans doing truck things than 50 years ago), even using longer term loans to make it happen.
When the car market has been basically saturated for decades, how else do you "make line go up" than selling the same product (transportation) for more money?
