I think most of us want a gradual and slow collapse, rather than one big giant collapse. Yes, we will be very rich if the whole economy collapse and everyone on the planet start
using Bitcoin, but the main question would be, if Bitcoin as a currency would be able to carry that load, and currently the answer will be NO. {We are not ready ..yet}
I also thing governments will rather change to a digital fiat equivalent than Bitcoin, when it happens. They still need to have control, and Bitcoin does not give them that option.