I think it's a combination of everything mentioned so far, and more. The idea of "can he still sing" is subjective, especially to the man himself. Let's not forget the psychological aspect to this issue. I mean, we're talking about Steve Perry here. The guy who Cain said would bleed over every song they worked on. He's a perfectionist. He knows what he was capable of in his heyday and what he can or can't achieve now.
I think this is what Perry was mostly referring to when he was interviewed about him producing the live in Houston DVD. He mentioned how emotionally difficult it was for him during that process. I mean, can you imagine watching and listening to yourself at your peak, reliving the love and admiration from your fans at that moment in time, then snapping back to the present and hearing yourself speak with your raspy voice (let alone singing with it)?
If Perry himself isn't happy with the sound of his own voice, he won't sing, especially not performing in a live show let alone a tour. I think that's what's really going on here.
That being said, like liquiddrummer pointed out, raspy as it is, I still like his voice. It's not just the notes the man can hit, it's his overall vocal character. I mean Geddy Lee sings in tune and has hit some amazing notes in his time, but the sound of his voice, its
character isn't attractive to me (but I still like Rush

).
I'm more interested in new recorded material from Perry than seeing him live. Sure, I'd be thrilled to see him live, but I'd be just as happy if Perry sat down with Jeff Golub and did a whole album of songs like "Can't let you go" (only more vocally driven). Let him spend a year on it. Build the songs piecemeal in production so he can tweak every lyric to his satisfaction. I'm sure he's capable of doing that. The question is, will he? Probably not, but dare to dream...
