Johnny Cash put out his American label recordings as an old man and he regained relevance, Dylan started making great records again in his 50s, after 10+ years of mediocrity, and he garnered attention and acclaim. Springsteen, too.
so long as they don't try and pose as young guns, they'll be fine. a great album will receive the attention it deserves.
that's the problem... they're at this crossroads where they still try to compete with the young guns, but they're old.
the three artists you named didn't try to remain hip and cool with the kids, they just made good music that was relevant to their age and experience, and in that rejection of the mainstream, they actually were able to be come hip and cool with the kids agian.
u2 just seems to be at a point where they try too hard to be popular. it's no line's major fault in my eyes... they wanted to go down that expermental road and just make the record they wanted to make, but they couldn't quite cut away from making sure that it was also radio friendly!
radio friendly pop is great... experimental, trippy shit is great... but when those two mix, it just kinda confuses people.