How low would Bitcoin have to fall before it was no longer recoverable?
Price, in my opinion, would not dictate this. It would have to be something that would destroy the foundation and system on which it is built.
what you say?
What ever caused or causes bitcoin to fall back to $1 simply means that bitcoin will return back to not having any value at all, and that also means that bitcoin destroyed and will no longer exist in no time or going further in to the future,
For the now, I would say that, I have not seen any strong enough reason or something that is strong enough that could cause bitcoin to die, or destroy bitcoin entirely, because I believe that what ever pushes bitcoin price down to $1, it simply means bitcoin is dead for real, and chances of recovery is very very slim, people will simply move on with other crypto currencies, but this is if cryptocurrency as a whole did not collapse, as I personally have always viewed bitcoin to be the foundation holding the entire cryptocurrency market, anything that causes bitcoin to die simply means the entire crypto market will be dead as well.
My opinion though.