on the one hand I can't imagine it will ever go fully to zero because then people will buy them just for fun, keeping the price at least a bit up.

on the other hand there is a price where the network no longer has any incentive to operate. Whereupon... doesn't it just stop working / become easily forkable? in which case it seems like Bitcoin is perhaps uniquely unable to recover from crashing out of all things that can crash (a thesis which is consistent with it having no intrinsic value, lol)

On other hand. At some point you can't transact on it for good while. What is the price of currency you can not "physically" move? Yeah numbers of exchanges can move. But if no one spends energy mining and getting lucky there is no movement of bitcoin itself.