Just finished watching and immediately thought the twist was one of the greatest punchlines in cinema history! Like you, I really doubt it was unintentional; it's too perfect. It conjures up the sad truth that sunk a lot of silent film stars like Anny Ondra (Metropolis, Blackmail) and Erich von Stroheim (Greed).

It also explains why the studio would suddenly axe their biggest star without even offering him a talkie. Until the end, I couldn't figure out why they didn't at least try to convince him to give it a shot. The effect at the end makes us suddenly sympathetic toward him; maybe it wasn't blind arrogance that caused his downfall so much as it was his embarrassment at his 'handicap'.

I enjoyed this film the whole way, but it was that ending punchline that put things in context. Switching production from silent to talkie wasn't as simple as just sticking a mic in front of the actor. Conversely, a lot of great radio personalities never made the jump to television & film. It makes you suddenly wonder if the reason is they just weren't pretty enough for the camera. There are lots of hidden tragedies in this deceptively breezy film.