Would there be enough money in the exchanges? Would bitcoin fail?
If EVERYBODY wanted to dump all their BTC, the price would go to ~$0/
BTC... So yes, in this case there would be enough FIAT on the exchanges.
It's all supply and demand. If the supply is huge and the demand is 0, the price goes trough the floor.
Supply and demand will increase the bitcoin's value all the time. I don't understand your concern that bitcoin supply stopped with the zero cost fianlly. Whenever the cost of the coins increase adoption and supply issue will only take to huge amount. Even last year halving done the reduction of supply and mining blocks reduced. That is the only way to bump the bitcoin value.
I don't support your wrong point.
Because his opinion is right since if all the holder will change there btc to fiat the bitcoins would die and became no value at all since as you said it is based in supply and demand, and if all will dump it means there's no demand of bitcoins will be get and bitcoins will be outfamed for that events.
Exactly, the OP was giving a fictional example, "what if
everybody withdrew their coins in fiat"
I'm well aware of the bitcoin ecosystem, but the OP asked a fictional question, so i answered his fictional question: if everybody decided to dump their BTC, the price would fall to 0. If every HOLDER of BTC would dump their BTC, but there were sufficient new buyers (1:1) for every BTC sold, the price should stay roughly the same. If every holder sold all their BTC, but there was an increased demand from new buyers, the price would rise.