Here's my guess, they have a faith life. For example, it's rare to find the mention of God and good vales in many of the other music genres. Rap music includes lyrics about beating and raping women, killing, etc. The character of the hosts, presenters, and award winners are completely different when comparing other music award shows to that of country music award shows. I think there's something to this.
Let me end with: "Thank God for unanswered prayers." One of many times Garth mentions "God" or "The man upstairs" in his music, and good luck finding many people with the number of record sales he's had in his career.
The bottom line is you don't have to take God or good values out of music to be successful and maybe it's exactly what's needed to make our country a better place.