Here are some scenerios that can cause the price of btc to fall drastically. (In my opinion, it is highly unlikely and the possibility very slim).
(1) No way to trade bitcoin or exchange it for goods and services.
(2) All governments of the world placing a ban on bitcoin and bitcoin related activities making it highly illegal.
(3) The entire bitcoin network and nodes going offline making it impossible to even make underground transactions in bitcoin.
(4) Another crypto overtaking bitcoin and value and more people shifting investment to this new crypto.
sourceBitcoin is trading over $63k now and you are trying to tell me there's a possibility for me to buy cheap bitcoins?, stop giving me false hopes man, we both know none of these things been listed will make bitcoin to back to zero, expecially the no. 2 about government placing ban on bitcoin, over the years we have seen some governments placing ban on bitcoin, and yet their citizens still make use of it, the government can't ban a decentralized currency, because even the government don't have control over it.