The uncapitalized “country radio” describes any radio station that plays country music, no matter what the vintage or pedigree. The capitalized version (in every way), “Country Radio,” describes any radio station that exclusively plays the modern, contemporary incarnation of country music. The split definition allowed me to understand that when people in the industry talk about “country,” they mean the entirety of the genre; when they talk about “Country,” they mean whatever music fits into that radio format right now.
Shooter Jennings' attempts not withstanding, I'm afraid there's no way to put the "o" back in Country. Mainstream Country won FM radio a long time ago.