Of course. But if this is not possible, we're much better off with a system where at least actors cannot profit from being dishonest.
I think Bitcoin is a great example of a system that is not cryptographically secure per se, but still holds up because actors need to spend money to - temporarily - prevent it from functioning properly.
I think Bitcoin is a great example of a system that is not cryptographically secure per se, but still holds up because actors need to spend money to - temporarily - prevent it from functioning properly.