Though very unlikely in my opinion, $43 is definitely not impossible. But imagine the number of buyers there will be from bitcoin dropping to below $1000 alone. I'm pretty sure there's going to be A LOT, including me. Bitcoin at $43 isn't bitcoin being dead though, it's just bitcoin in a significantly lower price. The blockchain will still be up and running, so I'm pretty sure there's no death that's going to take place there; even if bitcoin drops to $0.01.