Most GPUs are used to mine ETH. It is by far the most profitable. Unless another POW coin becomes as valuable as ETH, demand for GPUs will drop precipitously.
If it was like last time (2018), prices remained higher than what they should have been for months after. Then Nvidia got the message about how much people were willing to spend on GPUs, and overpriced their RTX 2000 cards.
Even if the big crash that kills GPU prices happen, I'll probably still have to go second hand, since a brand new, better GPU than the one I have will still go for (albeit less) ludicrous prices.
How do people get that many cards? Myself and about 3 friends have all been trying to get a 3060 or better for the last 3 months to build new computers and none of us has gotten a card yet. This is a mix of following discords, knowing site stock times (or trying their ridiculous lotteries), and one friend has tried bots.
Apps like Nicehash mine the most profitable shitcoin using your GPU and convert it to Bitcoin. When the market pumps people buy up cards and use it to make good money.
ASICs presumably take up valuable chip fab capacity at a time where we are going through a lengthy chips shortage that has real-world manufacturing impact on real goods people use to perform useful work.
A lot of that particular shortage happened because everyone cancelled their preexisting contracts and now they have to renegotiate at a new cost basis, after the government has thrown trillions of new dollars into the economy.
ASICs have had shipping shortages for months now, there's probably a lot of people using GPUs for bitcoin again, on top of ASIC-hard "crypto""currencies" that always abuse GPUs.