Well, I am no expert, but let me say this:
Old games - crappy graphics, mediocre gameplay (for the most part) <=> cheap costs
Modern games - better graphics, better gameplay (for the most part) <=> higher costs.
New generation equipment - better graphics, better gameplay (I hope) <=> even higher costs.
Isn't it like gamer greed? I mean we (as gamers) want more of everything, immersions, pixels, story, etc, etc, etc. It costs more to add those extra details. That plus the costs of training staff with new equipment and there you go. I think it's common sense for prices to go up, not endorsing it, but it's the "greed for more details" that's making this emerge.