This is interesting as it relates to a thought I've been having these last 24 hours.
Am I right in thinking they've never actually formally announced a split? There are three occasions when such an announcement would be expected - after they decided not to continue post-CAS, after the 07 tour and now. Obviously they're no longer a live band and no-one would reasonably think they'd do an album, and it's unlikely they'd ever do any more interviews or public appearances but as PC once said, Genesis is a sort of "brand". It's like an entity. Well, that's how it is in my mind anyway. So, wiki schmiki.
Well, if they won't tour or record new albums, I would say it's really over, no?
To me, a group that is like a "brand" is Yes (my other favorite band), with its revolving door of musicians. Sadly, the "brand" has been seriously damaged for the last decade or so by lousy albums and subpar musicians, to the point where the band called itself "Yes" right now is a sad and very pale shadow of its former self. In other words, the current Yes lineup sucks real bad.
Thankfully, Genesis never went down that road. I saw the Genesis tour in Montreal last November and I really liked it, but when I left the venue, I thought that it was the right decision for them to stop. As a farewell tour, it worked out well, but on certains songs, especially on "Domino", you could tell that this was really the last tour.