"Alt-country" seems to be a catchall phrase, a nutshell description of music that defies category.
There is a sort of nebulous genre we are trying to capture in a few words, inadequately.
Been awhile since I drove across country, but I noticed the same playlists on every urban station - love to listen to standard country radio on a road trip - and only heard a good cross section on the smalltown stations. Corporations run the airwaves, friggin Clear Channel and all those guys, evil.
Heard a story on NPR about a train accident outside a small town up north and a cloud of toxic gas was heading, possibly, their way, and there was not one soul at the local stations to get on the mike and warn the townspeople - all programmed out of Chicago,robot operations unable to respond to an emergency.
Political censorship, witness the trials of the Dixie Chicks from Bush's buddies, leaves the listener with few choices on standard corporate radio - little else but Carribbean getaway songs, weepy pedal steel backups, drinkin/fightin/cheatin songs. Somehow a few great songs and artists manage to sneak in and say something real every now and then.
Maybe that is a workable definition: artists who can't - or won't - get played on mediocre mainstream radio.