IMO,  I don't think this kind of worst scenario is going to happen,  at least not in the near future. I mean BTC is not that valueable to begin with but through years it become so expensive and valueable because of it's special features and function.  So it means as long as btc still carrying that function and role, there is no chance to value it zero.  Idk about another coin (altcoin)  but I don't think so for btc