I believe you - some of the musical complexity of arrangements in these old productions would no doubt challenge any number of modern artists unless they resorted to AI assistance.

I found this under definitions of Cheese or Cheesy:
"the quality of being too obviously sentimental.
cheap, unpleasant, or blatantly inauthentic."

But it gets tricky - some musicians talent lie in the area of writing very catchy or hooky songs. So aren't they being 'authentic' when they make songs like that?

I'll probably get flak for this: I think a lot of the Beachboys catalogue was cheesy.
But that didn't prevent any number of their tracks from transcending cheesiness

When I think of what is 'Cheesy' I think of excessive pandering to any particular demographic's perceived characteristics or likes or things in a way that seems artificial or grafted on to the art itself.