I am also a Radiohead fan, but you may know that already.
sometimes that does not matter
Agreed, but on a live performance, hearing an ill vocal would do nothing for me. Some of these 'old dudes' seem to have retained their voices and others have gone. I was listening to a recent 'Phil Oakey' yesterday, and he sounds just like the Phil of old, live and now.
Hearing ill or wrecked vocal of an artist who once was great (and you remember it) would add more sadness, would only make you remember about the better times, better versions, instead of enjoying performance. imo.