It's a peril of aging. If you're a singer, especially the typical untrained pop music singer, there's a good chance your range will decrease with age. If you've gone to see some of the longer running acts you probably have seen singers who can't reach the high notes in their older material. Some acts will play their songs in a lower key to help the singer, radically rearrange them, or even skip some material at all.
But there's one band that might not face this problem. It being Christmas season, CBC Saskatchewan just played a version of "The First Noel" by the Crash Test Dummies. Remember them? If you do you likely remember Brad Roberts very distinctive low voice, which Wikipedia describes as bass baritone. Can a singer who sings in that range actually lose his high range? Presumably, but listeners are probably less likely to notice when they sing in that range.