Have your non-proggy friends listened to the album? If they have and they like it, why don't they decide if they want to see the show? With an extremely tight tour schedule like that of DT you never know if the singers voice is in perfect condition at a particular show. Judging by the shows of TA I've seen and the bootlegs I listened to JLB isn't doing "painfully bad" at all. A few bits are different from the CD (at every show), to preserve the voice I guess, that didn't bother me at all. In the third-in-a-row show in Milano he was sick, his voice was overstrained but, from what I heard, he still did well. In many of the shows he was perfect.
It depends on what your priorities in a live show are. I want it as natural and raw as possible, I never expect a live performance to sound like the album. (If JLB should ever start to use autotune on stage I'd stop attending DT concerts at all...)