The net unredeemed dollars invested in Bitcoin must inexorably rise, as each dollar someone walks away with represents somewhat more than a dollar paid by someone. No one individual must lose, but ultimately, some real person must lose every one of those dollars. People see others walking away with millions and forget this simple mathematical truth. Unless the value of coin can rise forever, once it reaches it's all time high, the amount in the game at that moment is the lower bound on the total amount that must be lost. The entire scheme pays the departing investors with money from new investors, and that's it--there is nothing at the bottom generating value. It's the purest Ponzi scheme in the history of the art.