Not bitcoin but other coins retarget every block by design, because they are more volatile I guess.    Theres no doubt any drastic change would mean devs take action not just leave it to hang, or it'd be replaced and exchanged to rival crypto currency is my guess.


It does raise a point though.  What is the use of all these difficulty rises.   Is it somehow helping security by open competition it constantly raises the bar beyond the reach of hackers or nefarious parties like NSA, etc