I hope this will never happen of course, but for who have invested capitals, it may be a question someone have answered accurately to avoid an important loss.
Bitcoin has already dropped more than 60% - 70% yet people prefer to hold it because bitcoin bounces back to a new ATH.
This firm belief has made people stubborn about holding bitcoin. If you talk about bitcoin going to zero then the chances of that happening are very rare.
The best thing to do in a falling market is DCA as it gives us a good average buying price which maximizes our returns at peak price.