I would be rather surprised if the prices of graphics cards offering similar performance as the PS4 had been significantly affected by cryptocurrency mining.
It isn't the graphics that impress me, so much, as the fact that my PS4 can actually send real 5.1 audio out to my home theater setup. It boggles my mind with how difficult that seems to be on my gaming PC.
Sure, my PC can sling a zillion triangles per second, but it can't make one stompy robot dinosaur shake my living room the way the PS4 can.
Does your PC not have digital optical audio out? Also any GPU made in the last 10 years should be able to do 7.1 over HDMI. If you have an Nvidia card make sure to install the "HD Audio" component when you install the driver.
Inflating the prices for the high-end also affects the price development of the mid to low end, because those don't exist in isolation from each other.
