I guess nobody on this board understands what has been going on for about 75 years on one of New York City's biggest AM signals--WOR. WOR, under several owners (Macy's/Bamburger's, General Tire, and Buckley--I've probably left out a few) has been substantially brokered time for more decades than just about anybody who reads this board has been alive. Among the brokered shows back in the '40s were Carleton Fredericks, Mary-Margaret McBride (possibly under the air name of Martha Deane), and many more. WRKO is no stranger to brokered time. They've carried Pat Whitley's restaurant show on weekends for several decades. Whitley buys the time. More recently, they've added Barry Armstrong.
The secret to making brokered time work for many hours a day every day on big major-market signals appears to be to recognize that you can't accept every offer to buy time that comes down the pike. The station needs strict guidelines on what kinds of shows it will accept. And until the schedule fills up with brokered shows, the station needs a good lineup of syndicated programs to fill the unsold time. WOR has had very long-standing deals with many of the independent producers who buy time, but I think another part of the recipe is a willingness to kick a show off the air if its producers don't live up to the guidelines that the station has set up and the producer has agreed to.