On one-person broadcast booths:
"Red [Barber} always felt it was far more effective to have one man talking to one person. And the best way I could amplify that would be to say, if I wanted to sell this man a car, would it be more effective for me to talk directly to him about how good that car is? Or do I talk to you about how good the car is and he listens to the conversation? Well, I think you'd agree, head-on, one-on-one is better....
"So it's totally different. And I really think -- I don't mean to criticize them, but a lot of teams have lost something by not having one voice, one (where) you think of him. In the old days, I mean, if you said Yankees you thought of Mel Allen. There was no other. You thought of the Dodgers, you thought of Red Barber, period. The Giants, Russ Hodges. But it's not so much that way any more. It's diluted, because there's a lot of different people. And in my mind, they might have given up something by doing a local broadcast like a network game. I don't think it works."
Nowadays we call this "branding". I would also suspect that one great voice would be cheaper than two mediocre ones. Of course everyone is so used to two voices, how would we even tell if there were one great one?
(From an interview in the PE.)