Being someone who grew up in Los Angeles listening to the legendary 93-KHJ, I would think the way to make a successful oldies station is to recreate what they did. "Boss Radio" as it was termed was an extremely successful Drake-Chenault format that revolutionized radio during that era. I firmly believe that if you follow that model (which really hasn't been done since) there would be such an audience surge in listenership that you could be a ratings winner AND make lots of money in the process. Who knows, you might even re-define the radio format. Playlists were very broad because the appeal was so create a station that does the same. Sure, play the rock and roll hits (Beatles, Stones, Who) along with some pop (Dave Clark Five, Raspberries), throw in some R&B (Otis Redding, Gladys Knight, Stevie Wonder) and maybe a bit of the mellower stuff (Dionne Warwick) with a splash of novelty (Herb Alpert and the TJB, Alan Sherman). Then, add announcers who have tons of personality and care about their audience. Not ones like we have today who talk down to their listeners as though they were idiots. The result could be something wonderful and may just revive radio. Either that or we're doomed.
Unfortunately, all this effort costs a bit of $$$ and most stations don't seem to realize that in order to make any kind of decent money, you MUST SPEND A GOOD CHUNK OF IT TO DO SO! Anyway, that's my opinion...(ought to be yours...hee hee). ;D