Yeah, I think some pickup trucks are bought out of vanity. And if they're bought for work by a construction worker or farmer, the tax advantages could make them very attractive. When you were in the US you must not have visited very many farms or construction sites.
Sadly, I'm neither a construction worker nor a farmer. I can get by most of the year with just my hybrid Ford SUV. It seats 5, and has never gotten less than 40 mpg. In winter, I switch to my old Jeep Liberty.