Not sure if you realize this, but the further we get into the future, the more money is put into creating a system and a game. Unlike 20 years ago when it cost like $50,000 to make a game, now it averages around $50,000,000. You can't possibly charge the same price for a game. Which is why video game prices have gone up by $10-$20 in the past 10 years. And they'll keep on going up in price, as long as companies spend much more to make a game. The same applies for consoles.
And now with Blu-Ray and HD-DVD capabilities, you have over 3 times the space to work with on one disc, allowing for much more gameplay, and features, and newer technologies to be packed in on one disc. The price of games and game systems will only go up, because there will always be the reace for better technology, more content, more gameplay, and new features. And anything that is new in the technology sector is obviously expensive.