I was just thinking that since Bitcoins is 100% on the internet, what would happen if the whole world adopts it and 20M bitcoins gets stolen by a genius similar to what happened to Bitfinex?
Bitcoin would become worthless. Bitcoin is nothing without demand...just like every other currency. There's nothing tangible about it. It only has value if a community of people agrees that it does, it's thoroughly based on trust.
The world would decide on some other currency to use to conduct business - likely one of the other 100+ alt coins in existence!
What's worse is during a time of calamity. Say there's a major world war, internet goes down, power outages, something significant...it would have a huge impact on access to the blockchain, miners, prices, demand.