What do people do when they buy a bike and half of the components are not what they wanted? Do they just sell them on eBay and take the loss?
I haven't bought a full bike in a long while. I usually buy a frameset and build up the bike to the specs. that I like. I like Canyon bikes but not their standard component configurations.
Yes, but usually getting the whole bike build is a better "deal" -- cheaper than buying the frameset and the same parts separately. I went through this dilemma just recently. You'll notice that in most instances frameset MSRPs are quite high compared to the full-bike build with this regard ie. an Orbea Orca Aero sold at the lowest quality build (105) is ~$3300 yet the frameset sold by itself is $3000. The wheelset being included in that build sell for around $300 by themselves, so it's a better deal to just get the whole build and then bin/sell the rest. You would be comparatively "eating the cost" for an unreasonably high upcharge if you just buy the frameset itself.
On the other hand, other manufacturers will only sell the bike with a full spec, so in order to get the frame you want, you are forced to buy the whole bike and then bin/sell the rest. This is a problem at the high end if the manufacture isn't offering a build with cheap components like 105 because the $300 difference in that example is more like $3000+. In my case, the BMC SLR01 in white was only sold full build with eTap.. I already have parts I want to put on it and a several thousand dollar swing puts it out of my price range. I was lucky enough to find a dealer who would take off the build and just sell me the frameset as the same MSRP as the other frameset-exclusive SLR01s.
In a perfect world, manufacturers would only sell framesets to resellers which then spec the bike out for the end-user, but everyone involved wouldn't get whatever sale margin/partner discount/rebate/etc that makes it profitable for them to sell everything as they currently do.