FWIW, the 4070 was $600 at the time. You could indeed build a great gaming machine around a 4070 at much lower cost, but a few things inflated the price for me:
* I included the fairly nice 4k monitors ($750) in the price.
* The motherboards were stupidly expensive ($450) since I wanted something with 10G networking onboard, to support the netboot setup.
* The super-long fiber optic HDMI and USB cables are on the order of $150 each (and each computer needs one of each).
* Rackmount gear, which is stupidly expensive when purchased retail. (Datacenters obviously don't buy this stuff retail, so it's a weird market.)
* I think I included the networking gear and some other not-per-machine stuff in the figure. My spreadsheet from the time shows $3,067.64 per machine before tax.
(I am not trying to make any particular point here, just providing data for those who are curious.)