Just because the salesman believe the the "space shuttle haul" commercial doesn't mean the buyers have to believe it. IT'S ADVERTISING -- DUH !
WE need to do our homework BEFORE we go to a dealer ... salesmen want to sell you a truck, regardless of training or knowledge. Some know more, some know less, some help you find what you want - but all are trying to sell you a truck, not satisfy your needs directly. If it satisfies your needs, it's often by accident ...
Disclaimer: Some salesmen really know the job, and really do it well. That's what you need to find, and that's why you need to do your homework first, so you can tell the difference between a good one and 'an idiot' ... :) :)