If they disabled mining on all GPUs and hardware not intended for that purpose, video card prices would return to normal in a month.
Unfortunately it's too late; we just entered the era in which every appliance consumes less power, yet there is an unprecedented demand for energy, and it grows steadily. What will happen when everyone on the planet will want their own mining machine on 24/7?
"They" == "those who can do that", that is, developers under their employers direction.
Not every sentence containing "they" is necessarily a flat earth like conspiracy.