It’s an entertaining and inspiring one-man show of songs and stories written and performed by a 91-year-old man (and by the way, has there EVER been a one-person show by anyone of that advanced age?), that was filmed without an audience, and moreover, before it ever had a chance to play any public performances, and now getting a world premiere in this beautifully filmed digital presentation. By my book, that makes it a tremendous achievement of both confidence AND craft.
To nitpick the piece by calling out one commonly used rhetorical device (one that as you say is often a part of these things) and by saying his voice doesn’t sound the same as it did on the cast albums in the 60s and 70s (!!a,) - but then saying “I’m not a fan of concerts anyway”, even though this show is hardly a concert – I think there are only 8 songs or so in the entire piece – well... that seems at best a little bit like you’re missing the point, and at worst downright churlish. So while it’s probably unfair to say maybe some audience are stupid, I’d simply suggest that some audiences can’t appreciate what they’re given and tend to see the glass half-empty.