Strange, did GDAX run out of BTC? Sell side only showing 150BTC to over 7k USD. Maybe it's the coinbase inside traders that have been dumping and now caught low on ammo.
Clearly, regardless of price, as time goes on more and more BTC goes out of circulation.
Eventually there will be no BTC left. Only bid side in (unlimited supply) USD. Divide by zero error means price will be infinity.
You will be able to buy the whole universe with just one BTC.