(NASHVILLE SKYLINE is a column by CMT/CMT.com Editorial Director Chet Flippo.)

So, we now face the perennial "changing of the guard" in country music, eh? At least, according to pundits of commercial, mainstream country radio, that's what we're facing, although one revelatory newspaper article called it "the changing of the guards." But, make no mistake, the country music gatekeepers are calling for a "new guard."

Apparently, what it means this time around is that Kenny Chesney and Tim McGraw and their ilk are being shouldered aside to make way for the likes of Jason Aldean, Luke Bryan and Eric Church as the eminences of male country stars. And on the women's front, Martina McBride and her sisters are being supplanted by Miranda Lambert and the Pistol Annies and Lauren Alaina and their rowdy sisters.

Mainstream country radio continues to rule that roost. Although one significant change this year is that the country bible Billboard has changed its chart system to deviate from presenting only a country radio chart for songs. It now displays two songs/singles charts -- one for radio airplay and one for online sales/streaming and the like. Initially, it's inspired some country schizophrenia. Which is the actual No. 1 single/song of the week? Is it the No. 1 song on Billboard's Tuesday chart or is it its Thursday chart? That will shake itself out in the long run, but for now, that is making publicists and managers grab for two charts each week.

I've been watching this "changing of the guard" ceremony itself for several decades, and it really never changes much. Although there have seldom been newspaper or magazine articles actually calling it a changing of the guard.

Once upon a time, a wannabe, young country fledgling hopeful such as Loretta Lynn could travel though the South, with her husband Mooney driving, and with a boxful of 45s, look for all the tall radio towers and pull into the little stations cinderblock building next to the tower and just knock on the door. Usually, a DJ would put her on the air live on his show -- back when there were live local DJ shows -- and interview her and play her single after announcing. "Here's the new young singer Loretta Lynn with the song 'Fist City.'" That's how careers were built.

Until recently, country music careers continued to be built on radio tours -- million-dollar multi-city visits across country.

These days, country radio networks/monopolies are starting to eliminate all record label and artists' visits to local radio stations. They will be replaced by regularly scheduled presentations at the radio network's HQ (Do you like visiting Atlanta?) and to be booked well in advance. So much for spontaneity and for regional music bubbling up into the national spotlight. Regional hits? Forget 'em. A thing of the past. Too old-fashioned.

Do you remember -- or have you ever heard of -- the hit song "Harper Valley PTA"? Tom T. Hall wrote it, Nashville indie record mogul Shelby Singleton recorded it with a Music Row secretary named Jeannie C. Riley, shipped it out to radio and, almost overnight, it became a crossover sensation. It sold 6 million singles. Today, it wouldn't get past a radio conglomerate's mailroom.

That's change. But is it progress?

Country music has come down the pike in cycles for over a century now. The pioneers in the late 1920s were Jimmie Rodgers and the Carter Family. They weren't replaced so much as retired when Rodgers died an early death due to TB and the Carters went through family struggles.

But in the 1940s and 1950s, as post-war honky-tonkers such as Hank Williams and Faron Young and Lefty Frizzell were quickly eclipsed by Elvis Presley and the explosion of rock 'n' roll, it almost buried country music.

But Nashville fought back with the Nashville Sound, a sturdy mix pasted together with the silky sweet sounds of Patsy Cline and Jim Reeves and Eddy Arnold and others.

They, in turn, were turned out. Willie Nelson and Waylon Jennings and their Outlaw Music gang chased all the traditionalists for a few years. Then, here came the Outlaws being shoved aside by the Urban Cowboy movement with Mickey Gilley and Johnny Lee and associates. Just as things seemed to settle in peacefully for them, here came more usurpers. It's almost like high school royalty. You have one or two good years and then -- suddenly -- where are you? You're out the doors, out in the cold. Whatever happened to country music's vaunted "Class of '89"? Well, they were changed out. Johnny Cash and Willie Nelson and Waylon Jennings and Tammy Wynette, for God's sake, were all swapped out for little toy replicas. It happens to everybody.

It almost becomes like reading the Old Testament of the Bible: Garth Brooks and Randy Travis begat some new stars, and Dolly Parton and Tammy Wynette begat some also. And you get lost in a long trail of "begats." And we shouldn't even get into the Old Testament expression of "he went in unto her."

Now, should we?

Maybe I should just draw you a country music family tree, but it would be a huge, sprawling, asymmetrical spider web with dozens and dozens of names and hundreds of linking threads. Maybe I'll do it as a Christmas project next year.

At any rate, this is just to say that all things change. Sometimes for the better, sometimes for the worse.

By the way, why do you think it is that none of these new country "superstars" were invited to play the 12-12-12 concert?