Subprime really wasn't connected to the larger market that much, only in similarity of sector.
Same goes for crypto, it's the subprime of fiat right? While bitcoin itself may not be able to print money, other cryptos DO simply by being created. And also bitcoin itself now forks often, thus doubling and pentupling itself. Regular fiat rarely does that (except in the 1930s when the US gov't spot-reduced the value of the dollar to stop specie payments).
A subprime crash can create a feeling of poorness from once heightened wealth, and that can create tightening of the belt, just like crypto rising creates the opposite ,no? Almost a trillion in crypto has been created from nothing, and those crypto millionaires spend money. That creates a rise in spending, which will create an even worse stoppage of spending on the "other side" if crypto bubble collapses.