Heres my opion, take it as such
There are many products are are better quility then others, often times these cost more. (not always but often) for example the beloved sovergen. It is more expensive then many waxes but does a better job.
Often time you can do an ok job with a cheap product or a great job with a higher priced one. Again this is not always true, and i understand its more prep then anythinig, i do know how to detail a car.
If you need to purchase a more expensive product to do a better job and make the customer more then happy.
It is also a business, the goal is to make money, as costs increase profits decrease, you goal is to raise profits, for this reason often time the cost must be passed on to the customer.
Also when the cost of detailing increases your target market changes. For example if you wash cosrs 5 bucks then you will get people who can afford 5bucks.
If you charge 100 bucks you will only get customers who can afford 100 bukcs (often time with nicer or newer cars, i say this out of personal experince)
For a conclusion i think i have to say that statement is true to some and not to others, ieach business has to evaluate the makret and the business to decided if they can follow such a principal or if they should use a lower costing product
this is all just my opion
Mike