I also know that a station needs advertising to be successful. If I were an advertiser, I would be more inclined to advertise on the higher-rated KLAC or KSPN than on KFWB.
You have read David explaining the margin of error in ratings calculation, have you not?
Taking that "wobble" into account, all of the sports-formatted stations have approximately the same rating, and the agencies know this, and the agencies don't care, because ... (let's all say it together, kids):
The ratings do not matter when the format is Sports.
And if ratings don't matter, then why are Sports Radio 710 and Sporting News Radio 1540 no longer around?
710 was poorly done and did not properly leverage the Golden West sports package of Angels/Rams/Bruins.
1540 was the victim of financial problems at its network and was sold off along with the two other O&O stations. It also scraped the bottom of the barrel, for the most part, in terms of live sports coverage: At various points in its history, it had San Diego Chargers football, Westwood One sports programming not cleared by other stations in the market (NCAA basketball, PGA Tour golf tournaments, the Masters Tournament, selected NFL games, and Notre Dame football), USC basketball and football (the loss of which to KSPN in 2006 apparently being the reason the station was sold to Radio Korea a year later), and NASCAR.
Although you don't ask, 107.1 "Sports To The Max" was trying to do sports talk without a significant amount of live sports programming. They also carried Notre Dame for a while, plus the two NFL teams from the Bay Area (!) -- the 49ers and the Raiders -- and the Ice Dogs of the International Hockey League. Of course, they came and went by 1992, before either KMPC/710 or KCTD/1540 made their attempts.
There is one other factor which comes into play when you ask about those early attempts, and that is the fact that since then major 24/7 networks have come into existence (ESPN, Fox, CBS, NBC) and there are economies in station operation from carrying network programming, especially on weekends.
Now please stop trying to come up with questions you think I can't answer, Steve. There isn't some magic "trap" you're going to get me to fall into by attempts such as the above.