One possibility is that it's because the stock market seems like a good buy for speculators right now. The stock market does have an underlying value long-term, in that stocks are pieces of companies that produce products. The true value of that is always uncertain, but various measures indicate that it may be approaching reality (after a long, overheated bull market).
Crypto is more purely speculative, with no real underlying value aside from the hope that it will some day become the fiat currency of some nation. (Fiat currencies have a "value" in that they are the only thing a government will accept.)
So it's possible that people are seeing bargains in another market. They need to move through fiat currency in order to buy it, but they don't hold it long enough for inflationary measures by central banks to affect it.
Crypto is more purely speculative, with no real underlying value aside from the hope that it will some day become the fiat currency of some nation. (Fiat currencies have a "value" in that they are the only thing a government will accept.)
So it's possible that people are seeing bargains in another market. They need to move through fiat currency in order to buy it, but they don't hold it long enough for inflationary measures by central banks to affect it.