If all the Bitcoin users refuse the spend their Bitcoin and decide to just hold all of them, then the price of Bitcoin will not move. Bitcoin's price will not increase, it will not decrease as well. No movement will be detected until somebody decides to sell their bitcoin or until somebody enters the bitcoin world and decide to invest some money into Bitcoin.
I disagree with this if no one spends bitcoin, it means that there is not a bitcoin economy, and if that happens then that means that there´s not demand for bitcoin and then the price will plummet like a rock.