What generally happens when mining becomes unproffitable is the miners themselves refuse to sell bitcoins at a loss.

This drives up the price of bitcoin.

Then more miners come in when profitability increases.

So on and so forth.

There is generally a 3 month delay in the shifting of the bitcoin price,

It happened when the reward halved. It happened when difficulty increased when ASICs arrived on there scene.

Believe me guys, it'll happen again.  SO INVEST ALL YOUR SPARE CASH IN BITCOINS! NOW!!