Just a couple comments (no sales pitch intended)
I thought like many here that all soaps are pretty similar and had a hard time when developing a car wash trying to figure out why anyone would pay more for soap. I was challenged by awd330 and Boss429 to make as good if not better wash than the Sonax brand they had previously used , but was becoming impossible to find. (not sure if it even exists anymore) We went through quite a few prototypes, never even thinking of cost, but it had to be the slickest and most free rinsing product to even reach the Sonax level. Most of the prototypes were good, but not good enough for awd330 or Boss429.
The chemist was told to hold back no expense to make it better and thus was born Super Slick & Suds. When I was told of the cost, I said it would never sell, which is now a personal joke between awd330 and I, when we walk into the warehouse and it disappears faster than almost every other product I have. I was also told by my distributors that they were unhappy at the very low mark-up they make on the product, but I told them it would make their customers happy, and it has. Yes, most soaps will do a good to decent job, but some people just have a need to have something a little better. Yes, mgm2003 has moaned and groaned with every order, and i know he's tried almost every other brand out there, but with the care he takes of his vehicles, he always comes back.
The choice is up to each individual and when you break it down per wash, we are not talking about even the cost of a cheap cup of coffee or a can of soda. Most commercial detailers can not use higher end soaps for their business as they are watching each penny, but for an enthusiast, it's all about the results on their own vehicle.