An Answer to ur question is easy and i'll answer them with a question
1)how does a game will be look like let says 5 years from now?
do u think it will look like todays games or even more detail and stuff?

2)do u think that games now day using the full power of PS3 or XbOX360?

I'm sure the microsoft and sony is not planning to do business just for two or three year with their console do we
It's too soon to tell why sony use blu ray for their console and not dvd like other console maker..
Let's us see 5 year from now whether sony make the right move or a mistake to use blu ray disc for their games