How Did Music On The Radio Get To Be So Homogenized?

I can’t find one that’s widely available and ventures outside of the tightly programmed, not-so-distinct-sounding formats that its corporate overlords have decreed from the home office somewhere in not-Chicago. Indeed, I like to lump all those formats together into one uber format I’ll call “obvious music,” the songs you’ve heard before and expect to hear again from yesterday, today and, soon enough, tomorrow.