What makes Pop Country popular is that it is really just Pop music---melodies, chord structure, high-gloss production---with just a hint of Country, via the cynically-calculated and contrived lyrics sung with a deliberately-hick "twang".
The Country music industry has chosen to push this brand of Country, as performers/entertainers are easier to control and manipulate than are artists. EmmyLou Harris is going to do what she wants, not what she is told. It's a shame, because the audience that buys Pop Country would like real Country just as much, and in fact does when exposed to it. Jim Lauderdale's songs feature strong chord progressions and melodies, as do the songs of other Americana writers. And with quality lyrics, as well as accompaniment from some of the finest musicians in the world.
For Rocks fans, do ya'll know that Chad Smith of The Red Hot Chili Peppers is the drummer on The Dixie Chicks Taking The Long Way album? And that Mike Campbell of Tom Petty's Heartbreakers plays guitar on the album? Get hip, man!