Exactly. There are two types of music: Good & bad. That's what Duke Ellington said.
In Muscle Shoals, Rick Hall ran the FAME recording studio built on that same idea. In Memphis, they did the same thing at STAX.
After doing a few AMTs and some callout, I'd say that in radio there are three kinds: good, bad and mediocre.
An awful lot of "it's ok" responses are gotten in testing. Usually, that means the listener would not tune out if one is played, but if there are two or more in a row, they would. For one, they think, "OK, a good one is next". For two, they think "this station sucks".
Of course, songs that are hated will produce instant tuneout if the listener is near their radio, such as in the car.
That's why that "mediocre" score, often considered to be a 4, 5, or 6 on a ten point scale, will not get play on most stations. It takes a 7 or above, with no subset (gender, age group, ethnicity, cluster group, etc) scoring below maybe a 6.8 to get on the playlist and even then with a very slow rotation and scheduling rules so that the low score song is surrounded by very strong ones.