Mrs. Garrison
Rock n' Roll Doggie ALL ACCESS
NLOTH suffered because of its own weakness for sure, but I think that a lot of people didn't come back from Bomb because they didn't like it in the end, and a lot moved on to Lady GaGa. And I think a lot of Bomb's success came off the Beautiful Day wave, and the eagerness for more U2 that followed.
Those fans that didn't show up for NLOTH weren't lost with the record, they were lost in between 2004 and 2009, a long gap which probably explains a lot.
You really have no way of knowing any of this, but I will give it to you that Beautiful Day created some kind of wave. I think Vertigo got a lot of people's attention and sold a lot of copies for Bomb. Some people may have been disappointed that there weren't more songs as loud or rocky as vertigo on Bomb, who knows? Those people would have been disappointed with NLOTH, because that album was rather tame by comparison to the previous records.
If fans actually went from U2 to Lady Gaga, which is a stretch, but if that's the case then I think its possible they come back to U2 with this new record. I say this assuming that U2 has a catchy new single for the new album, plus the super bowl commercial/hype/buzz that goes along with that, Danger Mouse, etc. Also, from what ive heard, Lady Gaga isn't as popular as she used to be, I guess anyway.