This isn't why, in the end it doesn't really matter when it comes down to how much BTC is left because it just depends on whether miners can continue to make their bottom line. If they can make their payments on everything, they won't be too worried about what the price is. It's when the price drops below something that allows for them to continue operations that an issue becomes apparent for them.

The remaining 4 million just won't have too much of an impact at the end of the day.