DJ writes:
Something nobody had mentioned is the fact that wholesalers do not
want to deal with ignorant homeowners/DIYers buying small quantities
and all the nagging problems that come with them. Having a
contractor's license and being in business implies some level of
knowledge and/or experience in the use/application/installation of
said materials. The wholesalers are not set up to offer
help/instructions to the uninformed, inexperienced user; the big box
stores are...

I agree. But, this is a business decision on the part of the supplier
who needs to decide who is customer is and what is the cost of serving
any given customer segment. This is independent of the sense of
entitlement that contractors feel to receiving preferential pricing
just because they hold some government license.

The next time you need a contractor to do some work for you, buy your
parts/materials via the internet then ask him/her to install it/them.
See what kind of warranty you get on the materials. It would be my
guess a smart, savvy contractor would charge you more on the front end
to cover what he/she may be losing from his/her normal price structure
and for the possibility of having to deal with materials he/she may
not feel is best for the application at hand.

My point exactly. Material mark-ups shouldn't be used as hidden
subsidies for contractor profits. I see nothing wrong with a
contractor charging me a fair labor rate (including sufficient profit
and overhead coverage) to install my 3rd party supplied materials.

On the other hand, unless the cost of serving me is that much higher
than the cost of serving a contractor, I don't see why when I am a
DIY, I should have to pay higher prices just because I don't belong to
a certain guild with government charter (read: license).

The advantage of today is that the consumer has choice. I can go in to
a supply house aware of the true pricing (via the Internet) and have a
real (or implicit) conversation with the merchant. In the end, in
return for convenience and service, I may choose to pay a somewhat
higher price than the Internet price or the high volume contractor
prices, but since I have other choices, the merchant knows that he can
no longer get away with charging me the old 50% mark-up.