Seven years removed from when they last played together with Jason Bonham on the drums. Plant doesn't want the night after night toil of screaming. An old lion who doesn't want to roar as much because his vocals are shot. He prefers smaller venues where he doesn't have to strain just to appease the masses. Page's playing has atrophied from non activity. His last foray with Coverdale was his best after the band's demise and that seemed like an eternity ago. Jones? He's the one that's unaffected by time and is content to do musical explorations other than the hard rock genre.
It would be a miracle for them to even attempt it. They're done...been done as a unit since July 7, 1980. Would I like to see them take one more shot at it? Their personalities are different now and have outgrown each other to an extent. Plant just doesn't have the patience for the other two or for the weighty expectations of the band's overwhelming shadow.