I always enjoyed Simon's live performance of "Bridge" on Live Rhymon'. It goes on a bit long for my taste, but the gospel style is a nice touch and there's certainly nothing wrong with his voice.
Obviously there's a difference between what he could sing in his early 30s and what he can sing now in his 70s. Time to call it a day, Paul.
I read recently that he announced he would retire after his latest tour. I didn't see this performance, and I guess I won't. Its unfortunate that his voice is gone, but I also read that his tour contains new music from a new album. I have to respect that at 74 he is still creating new music. Most professional musicians seem to average about five albums. He did it for far longer than most.