I can't find the right reference, but I remember that such "light trucks" (e.g. Ford F150) enjoy a different tax and tariff compared to cars, and that's why several car companies have pushed them to the market.
It's not just F150's and other "real" trucks. Car based platforms make up the bulk of SUVs now. They are only trucks in name for the purpose of gaming fuel economy regulations. The PT Cruiser was among the first to start this trend.
The tariff is on foreign imports, which results in domestic trucks being privileged over foreign ones. It has nothing to do with customers choosing light trucks over cars, and if anything, it should rather incentivize customers buying cars over trucks, as there's more competition there, and so presumably lower prices.
