Status of RX 570 / 580 availability and pricing?

I'm under the assumption that the RX 570 should be priced at $170 and the RX 580 4 GB at $200 or so. I'm basing this guess on the prices that I previously witness for the RX 470 / 480 4 GB. But currently I don't see a huge supply of the RX 570's on neither NewEgg or Amazon. The RX 580 4 GB models are in supply but are priced closer to $250.

What's going on?
 
Sam5127 It's fascinating that you mentioned this because yesterday I came across this article and these two YouTube videos:

PC World: Why AMD's Radeon graphics cards are almost impossible to buy right now
http://www.pcworld.com/article/3199257/components-graphics/why-amds-radeon-graphics-cards-are-almost-impossible-to-buy-right-now.html

goldfries: GPU Mining with ASRock H110 Pro BTC+ : Running 13 GPUs at once!
https://www.youtube.com/watch?v=EpksFaxkbPk

BuriedONE Blockchain: H110 Pro BTC+ NEW Asrock Motherboard! A BRUTAL 13 GPU's 1 Motherboard.
https://www.youtube.com/watch?v=TImqhByN1CQ&feature=youtu.be

I had no idea that bitcoin mining was still such a huge thing. Why the revitalization?