News is the biggest thing in crypto world which affects the prices mostly, if there is a bad news the price will dropped because people starts selling the coin, if there is a good news then price starts rising because people started buying it blindly. Thats how the prices go up and down.
Yes you have a point but for me. People or the users are the one who cause bitcoin price. Because I think if Bitcoin has a many users then it has a good price but if it has few users then it has a poor price.