Well, if you remember the sponsors that well you must listen regularly. Mission accomplished for brand identification advertising.
Now, have you been motivated to buy?. Oh, you rent space at the Y and they take care of cleaning the carpets? OK Sorry.
Seriously, I would hope that a blend of unique information and entertainment is a major reason why the audience listens to KFI. That would reflect its heritage,
The station began as a service to farmers who were already the founder's customers (although the "FI" didn't really mean "Farm Information" when the call letters were assigned) and carried two major farm programs daily for over thirty years. It also came to be known as a competing news source to the newspapers with the original Richfield Reporter (later migrated to the NBC Gold network, a Pacific coast subset of NBC Red), fruit frost warnings from Pomona and later KFI Calling (although station founder Earle C Anthony disapproved of acronym based slogans like " Keep Fully Informed on KFI"). Anthony saw his baby as a service first. There is a legend (unconfirmed) that he prohibited his time salesmen from even having a ratings book.
I had the privilege as a youth of wandering the corridors of the "old gray lady" on Vermont - which was what some called the KFI studios originally built for the flagship station (KEHE) of a Hearst radio network that never materialized because the boss was preoccupied with San Simeon and Marion Davies). I was in the old control rooms for the distinctly named five studios (Auditorium, Blue, Coral, Diamond and Emerald) and saw the telegraph keys which the older engineers preferred over the headsets to signal one another. The station had a flavor and camaraderie non-existent in metropolitan radio stations I've visited in later decades - I doubt if the current generation could even relate.
John Wesley and Biggie Nevins (who successor owner Cox Communications sent to take over) certainly couldn't - they literally threw out the trophies and archives, including the meticulous annual scrapbook Anthony paid a clipping service to maintain. Departing news director Ned Skaff fortunately retrieved them from a dumpster and ultimately turned them over to Pacific Pioneer Broadcasters. I doubt even he knew that the same clipping service maintained a matching set for Anthony's auto enterprises. They too survived the demise of the dealership and when I got to peruse them in the nineties were in possession of the Packard International fan club. Chuck Cecil was allowed to transcribe or take much of the record library before the balance was given to UCLA. Co-chief Engineers Headlee Blatterman and George Mason (both with the station over fifty years and sharing the title) retired and the in-house organ wound up being given to a Church.