So a few replies...

Metroid: for GRIN COIN, the use of GPUs is the only source of mining right now and our 570 16GB card is the lowest cost card that can efficiently mine C31 for GRIN. So there are still some buying GPUs for mining.

Lunobird, I will pass your request along. The 570 is an older chip but a tried and true efficient miner.

Badbart, ASICs are still a ways out and even then might not be as cost effective, especially with the planned branch coming up that changes the mining to C32.