First reason: Bitcoin price is now clearly overvalued relative the level determined by its public acceptance rate (if 100% acceptance rate means ca one million usd, then nowadays acceptance rate is not clearly 10% but rather something around 1%).
Second reason: if the economic crises will emerge, then Bitcoin falls much more than major stock indexes (just as during corona crises March 2020).
There is no reason as to why Bitcoin would fall to over 90% down. As far as economic crises are concerned, it would have to be something big, like a third world war, for my to even consider 10k Bitcoin. And honestly, even then I would doubt it. Because if something happens, Bitcoin is as far as I am concerned (as well as a large number of other people around the world) Bitcoin is still safer as a store of value than gold. Especially in times of crisis.