Radio shows were hard work

Even a radio program of only fifteen minutes like Lum and Abner must have been a full time job. First of all, each episode had to be written and rehearsed, at least to some extent. That would include the sound effects and announcements. The actual broadcast had preparation beforhand and wind-up afterward. Then there was the coordination with the network and the advertisers and publicity, not to mention the financial side of the enterprise. Fifteen minutes would pretty well swell to take all available time, I would suspect.