Based strictly on the sales of Heavy Rain, Quantic Dream's CEO, Guillaume de Fondaumiere, has theorized that perhaps it was used-game sales that caused the company nearly 10 Million Euros worth of sales.
He bases his theory on the fact that the amount of games sold doesn't seem to match up to the amount of players who have earned trophies. There are nearly 3 million people who have trophies for Heavy Rain, but only about 1 million of them bought Heavy Rain new. De Gondaumiere then went onto say that if games continue to sell this way, Digital Distribution might be developers' only option in order to break even.
Perhaps Quantic Dream's next title with Sony Computer Entertainment will prove de Fondaumiere otherwise for those of us who still enjoy our physical game copies.