Let us consider AM rock of the sixties, and such classics as; "Yummy Yummy Yummy I got love in my tummy", "Chick a Boom", "Hello I Love You", "We Gotta Get You A Woman", well that one's from the 70s, but it's still pretty horrible.
Donovan could write wonderful songs like "The Tinker and the Crab", then he'd turn up some piece of tripe like "Jennifer Juniper", that would get hours of airplay.
The Monkees were the world's first made for TV band. But "Last Train To Clarksville" and "Daydream Believer", are pretty good songs.