It’s interesting that LA Top 40 AM radio was so different than Chicago or New York, the 3 largest radio markets. In 1976 WCFL dropped Top 40 leaving WLS as the only AM hit music station in Chicago. Similarly in New York City, WINS and WMCA dropped Top 40 years earlier leaving WABC as the only AM top 40 station.
Well, in New York, you're overlooking WWDJ, which jumped in (1971) the year after WMCA dropped out (1970). And that was five years before the shakeout in Chicago, with 'CFL getting out of Top 40 (1976).
In Los Angeles, KRLA essentially bailed on Top 40 in 1971, going album, as had KDAY a few months before it. And for a year, KHJ did have Top 40 on AM all to itself (unless you counted KEZY, which was an Orange County station that was listenable in
some parts of L.A.
Then came KROQ-AM for a little over a year, and it was gone (again to album rock, under the same PD who flipped KRLA---Shadoe Stevens).
KHJ really had Top 40 on AM all to itself from the fall of '73 (KROQ's flip) to the day after Christmas, 1976, when KGBS became KTNQ. Storer had considered going Country and ended up regretting not having done so. In fact, until it made the decision to sell, it had announced that it was going to correct its era and take KTNQ country in 1978.
And KFI really only made the move because of the PD they hired---John Rook. Rook did what Rook knew how to do, while telling Cox that it was really just Adult Contemporary. A different PD probably would have continued with a personality AC.
If KGBS and KFI make different choices, KHJ is the last Top 40 on AM in L.A. (Somebody’s gonna mention The Mighty 690, but it’s Tijuana and if KFI and KTNQ never happened, who knows if it would).
WNEW AM in New York featured older standards from the Sinatra era.
WNEW had been successful with the standards approach and never saw the need to morph into AC. That wasn't the case in L.A., where KFI and KMPC began losing significant shares in the late 60s and early 70s.
Standards finally caught back on in the early 80s for KPRZ (1150) and then for KMPC.
I wonder what made Los Angeles different then.
L.A. was always chasing hipper, newer and younger. While teens in New York were drinking Coke and requesting Leslie Gore records from Cousin Brucie, teens in L.A. were smoking weed and requesting the Doors from B. Mitchel Reed.
KMPC and KFI wanted 18-49 adults---which meant aiming for 35-year-olds. They weren't gonna listen to standards. WNEW had enough 45+ adults who would in their listening area to make it profitable for them.