The irony to me is that in the 70s, ABC was competing against (and losing to) Metromedia rock stations in NY and LA. (the gap between KLOS and KMET was huge in 1979) It was interesting they chose not to do it in SF.
I can't speak to New York, but in L.A., Sam Bellamy finally found the right approach for KMET to counter KLOS. A loose, wild, fun atmosphere and exactly the right records. She almost tied them in the spring of '77 (2.7 to KLOS' 2.8), and Tom Yates, who'd been programming KLOS since the fall of '71, resigned:
KLOS pulled ahead by 0.8 in fall '77 under new PD Frank Cody, and then KMET overtook them in spring of '78 (3.6 to KLOS' 2.8) and widened the lead in summer (4.8 to 2.3).
By spring of '79, KMET had a 5.8, was in second place and stayed in the top three stations for a year (peaking with a 6.4 in the summer of '79). KLOS was pulling low-to-mid 2s and was ranked between 13th and 18th.
KLOS replaced Cody with Tommy Hadges in May of '80, he brought Bob Coburn back from Chicago, and started promoting Frazer Smith's morning show.
KMET fell off a cliff in the fall of '80 (8th place with a 3.6, though KLOS was worse---15th with a 2.7), worked back up to 3rd place with a 4.6 in the spring of '81, but KLOS was climbing and edged KMET by 0.2 in the spring.
After that, it was kind of a see-saw battle, with both of them unsure as to how (or if) to respond to KROQ. Sam Bellamy left KMET in September of '83 and the station began the slide that ended with the flip to KTWV in February of '87.