This is just plain wrong, sorry. That would hold true for a Ponzi style investments, that is, a zero sum game. Since Bitcoin has uses beyond sheer speculation (that of "buy low sell high"), this immediately renders such statements invalid. Someone sells a bitcoin with a profit, and someone else buys it, then the price drops. It appears that the latter is suffering losses, but if he is not going to speculate but use it beyond the exchange (say, to pay for services), the matter becomes more complicated. And it may turn out that everyone wins in the end, despite the price decrease...