There's an outside possibility that mining will drop off so quickly that the 2016 block difficulty recalculation will struggle to happen, but honestly if that h

There's an outside possibility that mining will drop off so quickly that the 2016 block difficulty recalculation will struggle to happen, but honestly if that happens there will be a consensus fork. Thankfully what will happen if the price collapses is that mining will reduce. Bitcoin has been through a cycle of a "run on dollars" before, it has never died before.