Crypto is just a big hype seriously... Since people see DIY mining videos, they tend to spend much more on GPU's if they have the chance. Therefore GPU prices are high.. If you needed 1 Nokia 3310 in order to mine 0.1btc/week, people would've get 100 of them, and prices would skyrocket from 50$ to 500$ easily too... It's just high demand in the companys point of view..