Honestly I thought this two companies won't allow Vitalik to switch lol, I was wrong.
When their earnings come out in the guidance they always state that their business does not take into account mining profits. Right now their stock is dropping but its not because of end of POW its because most large cap stocks have dropped recently. Yields are going up and looks like all stock indicies will hit new 52 week lows and hence why Nvidia is dropping. Plus all that non sense they had earlier with the Capitol.
They are a big company and they can survive without miners. However the next few quarters will be brutal for them because there is going to be a huge supply of used GPUs and many gamers will just buy used instead of paying 2x as much for new.