I've heard you say this before but it always amazes me David. Fontana, Ontario, Rialto and Rancho Cucamonga are big population communities clearly in the sphere of Los Angeles. I'm sure their residents consider themselves part of the Los Angeles Metropolitan area. Many probably commute to jobs in LA.
If the far eastern end of Long Island is part of the New York market, as is Ocean County NJ, all well beyond NYC's FM signals, why are these four California communities not in any market at all? They all hear the LA FM stations and a good amount of the AMs. Maybe I-15 should be the dividing line? West of it, Rancho Cucamonga and Ontario should be in the LA market. East of it, Rialto and Fontana should be in the Riverside Market.
Ontario has 164,000 population, Rancho Cucamonga is 177,000. Too big to ignore.