I like jazz a lot. I used to listen to KKSF all the time, but honestly I can only handle the same 20 songs over and over and over and over again for only so long. The only time I tune in to KKSF now is on Sunday night when they have their 'Jazz Cafe', where they play a very nice variety of jazz and rarely do they repeat songs. If they did that all day every day, I think they'd have a bigger audience. Repitition becomes very boring after a while.
The one thing I think that is missed in this format is that most jazz fans like jazz for the variety (among many other reasons), and there is little in the way of variety in this current format. And yes, I know that 'top 40' is popular, but its a different kind of music with a different type of audience. Why are stations like KKSF afraid of expanding their playlists? I'd listen to them all day if I could be assured of not hearing the same song three times in an eight-hour period.