Originally Posted by
dsaul
There is no profit to be made from purchasing parts at retail prices and building a complete bike, no matter how unique it may be. Any shop with wholesale accounts will be paying far less than retail for those parts. No matter how well you shopped for prices, no one is selling at cost. Bike manufacturers get parts for even less, because they buy in bulk and without retail packaging.
This, 1,000%. Generally, a component goes from manufacturer to initial distributor (the folks who put it in a container and on a boat) to the secondary distributor (chain suppliers like QBP, KHS, etc) then on to the vendor. The price of any part reflects it's travel through that supply chain. A bike mfr. gets their parts by the pallet, often directly from the manufacturer.
Further, never expect to just put a bunch of parts on a frame and sell it at a profit. That's not how it works. Because if the OP can do it, anyone can do it, and save themselves that 4th, wholly unnecessary markup.