This is where U2 is at...
Every artist happens upon a time when what used to be easy now seems so hard.
Even Bob Dylan said, he doesn't know how he wrote his old songs. Youtube a 60 minutes interview with him, he'll say "darkness at the break of noon, shadows even the silver spoon"...etc. - He doesn't know how he came up with that song.
Lou Reed said something pretty much on point with Dylan, in an interview with Elvis Costello, he said, to some degree: "you don't start out with a blank page. Either the song is written already, or you don't have a song at all"
The Doors, in their debut album classic album DVD, John Densmore said "the muse was defiinitely around at that time. You don't own it."
I think U2 are just victims of what happens to every great artist. After a certain amount of time, what once was easy (writing songs), isn't so easy anymore. The muse is gone. The inspiration is gone.
Where I do find U2 making strides with their music is where they don't overthink everything and just run with a burst of inspiration, kinda like MOS.
I'm a songwriter, and i've found that these older songs i've written, ones that have been worked on to death, overlabored, just dont' sound so hot now. I think when U2 are working something to death (like SUC), it won't amount to anything great, because they are already trying to make something great out of something that isn't great. The best thing to do, sometimes, is just start over.
The whole thing with Bono saying "we don't need the pop kids" was just a statement of the times. At that time, 80's music was being swept under the rug, and everyone was getting off on a detached, post modern, cool way of presentation. That's where U2 was at that time. That's why it worked. The best thing to do was to denounce their former selves.
In the 2000's, U2 found that the best way to crack the top ten again was to be unapollogetic about their past. To be unembarrased about being "U2". That's what worked for them at that time.
I think there will come a time soon when U2 will want to do another 180...but at the same time, they are getting old. I'm not sure if the fire is there any longer, to do another aboutface and present to the world another version of U2. This just happens naturally. Bands get old, and they stop caring so much about changing shit.
Maybe U2 will be the exception to the rule, but most bands after a while just lose the desire to want to shake things up. If anythign, they just want to be heard.