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.
not spending is different from not trading. because even if there is no spending there will be traders on exchanges trading bitcoin for fiat.
not spending bitcoin means no usage for bitcoin (which will never happen) so in that case the price will be like an altcoin below $10 because there is not any real demand to keep the price up in that scenario.