And as I stated Skyrim wouldn't be in the same linear format as ME2 and FFXIII so the multiple disk would be hard to do other than cutting the world in half and putting them on multiple disks.
Which wouldn't work since in Bethesda games the player is free to roam wherever from the start no matter how hard it may be.
Standard DVD is impressive and has life for movies and video games to come. But I agree it is getting hard for developers. I doubt many games will be impossible to fit before the next gen of consoles though.