That's a tad drama queeny. I'm sure during 2014/15 there were periods where it was barely worth bothering. The big operations would be well capitalised enough to account for fallow periods.
As ever, if enough miners clear off it becomes cheap enough to mine to attract others after a sluggish period of readjustment.
And the price would go up, as cheaper energy costs would attract miners back.
Theres no way to go to zero, there will be always a mining cost which will reflect on prices.