what proportion of bitcoin is actually spent? i'm gonna guess that it's not very much. using it for shopping and all is cool but i think it's a little bit of a sideshow. most of the action is trading it and speculating.
the bigger question is if no one speculates on bitcoin what might happen?
Same thing: the Bitcoin collapse would take place. Just like Gold, Silver and all the others: magnates are taking care of them, so they will rise or fall whenever they want to.
Yes. Other currency will take over bitcoin. That will be bad because maybe if that will happen in the future, maybe bitcoin will be dumped at trading sites.