Well, on behalf of the clerk, she'd likely be required to promote the lines the store carries. Also, not everyone is as "into" trying different waxes etc. as some on this board are, so maybe she hasn't bothered to look for anything past what the store carries.
However, 3M does sell more than just the paste wax. They have the liquid "pure" wax and the cleaner wax, that I know of.
Meg's has waxes and sealants for pros.
One thing about the "industrial" waxes is that they are made for "volume" users. This may mean that some aren't as user friendly as some boutique lines, or it may mean that they don't have as nice a look as the boutique lines. Also, some "industrial" lines are not readily available to the general public. As well, some people don't want/need to buy gallons at a time, which some "industrial" products are only available in.
Anyway, The only way to know if you like something is to try it.