Why wont the computer stores around here build a computer for me?

Recently, I have started looking in to buying a new gaming PC, but have run in to a strange problem.

I have decided, that I want to spend about $2250 on the build, SSD drive, a Titan GPU, 64 bit system, 16gig ram, etc.

However, I have run in to a weird problem, in that the stores don’t seem to want to take my money.

I have been to three stores now, and they have all told me the same thing, that with $500—$600 I can build an awesome gaming computer, and that I don’t need to spend so much, and that they are not really interested in building a big rig for me.

Does anyone have any idea why this is happening?

Will they lose money somehow if they build me a big rig?

Are they scared that they have to guarantee such an expensive build?

Why do you think they wont build this for me?

(I even offered to throw in $200 for the work of building it for me)

I would build the thing myself, but since it has been some years since I built one, I would be more comfortable if a pro built it for me.