or ... or ... and this is just food for thought, they've realize they've become this, and the new album perhaps sounds a bit like old guys trying to be hip to the kids.
so they finish out the tour as a final "biggest band ev-a!" hurrah, tear it up at Glastonbury, and go back into the studio and the next album is ... "mature."
maybe?
Anything's possible, let's hope this is the case - they stepped back, realised they had songs produced by will.i.am and RedOne, and said "Guys what the fuck are we doing? We should be leading the path of music, not hitching a ride on it!" And have decided to make something groundbreaking in a properly committed atmosphere without tour or spiderman distractions.
However, going on recent trends (ceasing to play NLOTH songs, no fourth single, calling the album "too dark" because it didn't sell well, whilst saying that they want the next album to have lots of hits), it's far more likely that they looked at the songs they had, believed that they couldn't possibly be hits, and decided to scrap the material, and work with Eno/Lanois/Lillywhite again.
E, L +L won't necessarily bring about another NLOTH-style debacle - i think the reason that album flopped was because it didn't have a clear direction - started off as an experiment, ended up needing hits, came out as a compromise that satisfied neither criteria. So as long as they have a clear purpose, they're probably very capable of getting hits (AND songs we all love) out of their usual squad.
And i don't think that's a bad thing - it wasn't Eno or Lanois who wanted songs like GOYB on the album, it wasn't even u2 really, it was more of a panic (i'm guessing). And judging by NLOTH's reception, if they do work with the usual guys, it will be more focused and less contrived, which will mean less GOYB, and more BD/One (hopefully). The only downside with this is the wait!