Why does FM radio sound so good?

I have always compared my systems over the years to FM rock, etc, and, until lately, was always disappointed that I did not have that sound, even in the car.  What is the history of station playback equipment at FM stations?  I suppose it's all streamed or files now, but didn't they use single-song tapes awhile back?     
Classical and college radio sounds excellent thru my home system; clean is a good way to describe it. I’m using a vintage Denon tuner.
Rock stations sound good as well, except for the loud compressed bass.

Public radio stations sound fantastic. Mainstream Rock or whatever still compress everything to death. I swear a station the next town over adds reverb to their content. 

A lot has to do with the fact that most of us grew up on/with the sound of FM and it gives us the warm and fuzzies, provoking lots of positive feelings that lie deep down within us. Nostalgia, if you wish, and it’s a good thing.

All the best,