As a natural born American, some of our industries confuse the hell out of me. Why are used car dealerships so scummy? Why are there (overpriced) mattress store

As a natural born American, some of our industries confuse the hell out of me. Why are used car dealerships so scummy? Why are there (overpriced) mattress stores on every corner? Why do we sell prescription drugs on TV? Mattresses truly are a weird one though. You can see how overpriced they are by the mere existence of these massive stores with allegedly-valuable inventory, that are always empty, because people don't need new mattresses that often! Of course, they're ridiculously overpriced so you can get great "deals" on them as they're always running tax-free sales, etc. Thankfully when my wife and I went to try out mattresses for our fancy new big wood bedframe, in the process of trying everything from $600 up to $3000+ (california king size pricing), she declared the cheapest one her favorite, and that was that!