blu-ray wasn't needed. the ps3 and 360 were outputting the same games essentially. so this benefit you people are talking about doesn't exist. and unlike kinnect it added about $200 to the console price. while I agree kinnect isn't essential in the slightest, it adds far more to what the console couldn't do without it than what ever invisible addition the blue-ray drive was.
http://imageshack.com/a/img801/6426/f7pc.gif
^Yes that's me ripping it up in the GIF. :)