Don't you think the stakes are higher than they've ever been for the band? To me that would mean they'll go through even more songs than usual, do more editing than usual, etc., because they have to live up to ATYCLB and HTDAAB.
This would be the third album in the "neo-classic" U2 cycle, so they can't miss.
Meaning, I think, no album before 2008 or thereabouts. Would make sense given that the first two were four years apart.
Besides, the World Cup is coming up and you can't convince me they'll get serious work done in the next month.