If 20% a day drop price then 5 days bitcoins price would completely depleted which means it would be dead on 5 consecutive days of sudden price decrease. 1st day decrease it can still being  handled but on 2nd day im sure panic would really be there 40% drop isnt a joke which means theres something wrong in bitcoin how much more on 60% drop. You cant say that you would buy even more on those situations. You would really be hesitant on doing such thing.