I dont know how market cap is calculated but as per my understanding that in order for the price to reach $0 someone will have to buy it at $0 or very close to it. i wonder why would everyone end up selling all their bitcoins for that low a price.
i dont think the price could go as low as $0 or even below $100. there are about 4 mil bitcoins locked away which are not accessible anymore. some by FBI some by bitcoin founder and people losing wallets or accidental deaths all contribute to it. so those 4 mil bitcoin cannot be sold which as per my understanding will hold the price at a certain baseline. if i were to guess that baseline i would say it is $1000
why would price go down that low. the only reasons i can think that could happen if there is a big security flaw in bitcoin code which allows hacks and the developers of bitcoin cannot fix it and it results in total loss of confidence.
another reason why it could happen is if all the govs on whole planet agree on cracking down on bitcoin investers, traders, holders, etc. we know thats not going to happen either.
The chances of bitcoin price sinking to what you mentioned in your question is almost 0 as well.
one more observation, if btc was to sink that low, all the altcoins would have zeroed out well before that happens.
