I find that the bands stay strong, maybe even get better, with age. But the singers lose the range, so it depends on how they relied on the voice. Raspy rockers that didn't hit the high notes do okay. I've enjoyed Springsteen and Billy Joel. If they're considered old Green Day, Wheezer, Ben Folds have all been great to awesome.
Hair band singers just can't hit the notes. The shows are still good because of the bands, but G&R, Motley Crue, etc. are just meh. A counter to that is the bands that have replaced the singers with younger guys. Journey and Queen with Adam Lambert were good.