The difference here is that Sony took the gamble when they didn't have the money, MS has always had cash lying around. Bravia has turned Sony around recently, they'd look spectacular right now if not for ps3 holding them back.
If you think Bravia is the source of Sony's recent profits, you should think again!
Read through post #14 of this thread here for insights into Sony's modern day profit drivers:
http://forum.beyond3d.com/showthread.php?t=48083