Market cap does not mean that there is exactly that much money in there. It's just the total possible amount of Bitcoins multiplied by current price.

All it would take to get the price that high is if some billionaire decided to buy a few 100k of coins - all the coins for sale would get rapidly exhausted and the price will shot up unconstrained, and would likely linger there for a while, supported by the extreme FOMO that would follow.