I'm not so certain that Joe wanted to retire. As romantic as it is to suggest he knew all along and didn't say anything to take the spotlight away from Sam, he may not been thinking retirement at all. If you listen close towards the end of that final game, he talks about having worked with Kenny in the past. To me that was him looking forward to working with Kenny this season. I'm not sure if that was him simply playing along knowing what he was going to announce. That would be quite calculating of him in that moment.
I have it on good authority that Chris Drury isn't friendly with the broadcasters so don't expect Dave Maloney to get promoted to the TV booth as outspoken as he has been on the radio.