I 78, I love your analogy. It's right on. The other analogy I would use is a downward spiral. At the time BA took over the format it covered a pretty wide range of musical influences - pop, rock, world, R&B, funk - and energy levels - there was uptempo music on a lot of NAC stations. Then BA came on with the original SJ Network and said songs had to be relaxing and R&B oriented. No more "screecing sax" or "rock guitar solos". So that narrows the focus from the get-go. Then the hook testing came in. Certain types of songs do better in hook testing than others because familiarity is such a factor: covers, pop songs and oldies "test" better than original instrumentals 'cause the listener can recognize them better in 7-10 seconds. So as more of the covers, pop songs and oldies showed up at the top of the test more and more original instrumentals were dropped from the playlist. So the focus gets narrower and narrower until we hit today's SJ format. Almost all covers, pop songs and oldies. That's not what listeners came to hear though so they have gone on their way and the Smooth A/C format just sounds too old, tired, and MOR for the average 35-54 year old. They will get their A/C and oldies on an A/C or Urban A/C that does that better anyway.
I think one of the biggest "killers" has been the research method..it created an inward spiral that has ended in a voice.
I would say Kenny G and Boney clones more than Koz clones though. Koz actually has gotten a lot of flack from the consultant over the years over songs like "Honey Dipped" and "Together Again" because they were not "relaxing" or "R&B" enough for the "format" but WAVE listeners were responding to them so they kinda snuck in the back door.