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?
If the price of Bitcoin drops to $0.01, someone could potentially buy all available Bitcoin supply by placing a limit buy order with amount $210,000 and price $0.01. The next trade in the BTC/USD would then show a price of +infinity.