One of those reasons is that it is cheaper to let a CPU spend 30 hours rendering a frame than to have an artist sit down for 30 hours trying to make it look right, using a bag of tricks.there's a reason all high end CG uses physically accurate rendering. traditional rasterization is a box of tricks that can make a very visually pleasing image, but simply can't accurately model light.
.
If using a bag of tricks was cheaper to do than raytracing, the industry would do it (and did do it when CPUs weren't fast enough)
BTW They don't always get to keep the cards.Let the hardware manufacturers charge the reviewer full price for the card. Then you get an unbiased review since hard earned has been spent