Couple of singers who's voices have aged well:
- Mick Jagger
- Steven Tyler (though I haven't seen him in a couple years)
- Robin Zander (not perfect, but for all the touring that Cheap Trick does, it's amazing he can even talk)
- Jon Anderson (not sure he could do a 100-date tour, but I saw him right before the COVIDs, and he hit EVERY note)
- Paul McCartney
I'm giving an honorable mention to Robert Plant. He cannot do what he did in 1971, at least not on any sustained basis, but I actually think he's a better singer now, and has a richer, fuller voice. Plus, if "Celebration Day" is anything to go on, he's the poster boy for "Not as good as I once was, but once I'm as good as I ever was". His voice has really turned into an instrument in the last decade or so.