All musical genres evolve and change. What used to be called "country" is now called "bluegrass", and relegated to stations like 1110 AM in Washington, PA.
Thank you, Realist. Today's country music has its roots in early rock, rather than hillbilly, as it was called back in the days of Hank. My parents, who both grew up listening to the Beach Boys, Elvis, etc. don't find the simplicity that attracted them to rock n' roll in the first place. Though some artists are trying to get back to the basics (John Mayer and Michael Buble are good examples), country has pretty much maintained a constant.
As for you, corporateradiosucks, you're using crossover country music artists as an example, like Shania Twain, Faith Hill, etc. I'm talking modern country artists that have stayed true to their music, like George Strait, Travis Tritt, Terri Clark, and others that you won't hear on rock or AC stations.
More than that, no one SUDDENLY changes their tastes in music so dramatically. It evolves. A person may start listening to CHR, then Hot AC, then AC, then oldies, and then country. It's a protracted chain of changing tastes.