tuners and the quality of signals/source

If we believe in the "source first" theory then the signals that tuners receive are less than ideal in comparison to the source produced from a CD player. I do not believe that station use anything as good as our Naim players. For that reason, why buy expensive tuners? My guess is that when we listen to music from different source our expectation changes. as as as I concern, the tuners give you the chance to listen to specific program (classical, jazz etc.) that you dont have large collection at home. I particular enjoy the comments that the classical station made before thay the tunes. Most of the time those comments are quite educational (for me) when they talk a bit about the composer life etc.