@ RolStoppable
Although you add a strong point into this discussion, note that distributing games through the PSN is a very cheap alternative available to PS3 developers. WIth regard to the bigger projects, they have the resources.
Blu-Ray disc production costs are dropping quickly and with regard to movies is now generally cheaper than HD-DVD, as many / most HD-DVD movies use dual-layer discs and Blu-Ray movies are currently supplied on single layer discs.
Note that the average game is priced way above Blu-Ray movies, so with regard to games the added cost is less of a factor as compared to movies (percentage of the total revenue).