Did you think of this: If the stock markets crash the money that was owned in those assets would be "lost". Therefore there will be no more money to enter a new market, in this example, into the crypto market. Hence your statement is incorrect.

I still dont understand why some people keep thinking of crypto markets and fiat markets to go against the movement of an economic crisis - they dont. Rather in case of a crisis they both drop. Sometimes we might see opposite trends but that applies more to fiat vs precious metal market. All in all, you cant compare the two to move opposite because the source of money is still from fiat and if one crashes, the other will panic and sell.

Also dont forget that crypto owners that can be classified as whales also own a lot of fiat market assets seperately.