When Toshiba finally gave up on HD-DVD in February, I indicated that although Blu-ray had won the battle, optical media would eventually lose out to video downloads and video streaming.
Of course, I felt it would take quite some time for that to happen (though the apparent upcoming imposition of tier-based broadband plans may slow things down even further). Sony apparently agrees about the upcoming demise of optical media, at least in terms of the delivery of gaming software.