Perhaps it is you who lacks the common sense? If the phone powers down, it has reached the point where you have discharged it as far as you can, all phones do that. try charging it now.

The problem, as i see it, is that this phone still has SOME energy stored in it. If there was no power then it wouldn't even be able to turn on at all. So why does it have a "program" that says "when the energy is this low, automatically turn it off". Why save that little bit of energy if its unuseable. For all practical purposes, my phone is dead. But its not. It still has some energy in it. Why?