KOOL just played Sundown and Love Will Keep Us Together, two mid-'70s number-one hits that KRTH quit playing many years ago. But hey, maybe those songs don't "test well" with Los Angeles listeners.
They would test well today. If KRTH played them today every so often or on weekends, the audience would not even notice. Play "Puppy Love", then yes. Phoenix isn't much different from L.A. If anything, lots of retirees from So. Cal cities and certainly lots of Hispanics there.