Seriously, do you have perfect pitch? I don’t, so a performer who can hit a note is better than one who is trying to hit the original.
Personally, I'm a fan of Daltrey's comment "give me a bum note and a bead of sweat." I saw Daltrey belt out tunes with a few missed notes, but he's not tuning down the set AND he keeps swinging the mic while standing up.
Hitting a note after tuning down is akin to an Olympic diver doing a cannon ball. There's no sweat involved. It's copping out. If the song is in A♭, and I am paying $150 plus taxes and fees for a concert, I don't want to hear it in A. Take some of your earnings, hire a vocal coach, hit the gym, and deliver the songs the way you recorded them when you cared.
Yes, this is a First World problem. But I live in the First World.