I live outside of Austin and, for full disclosure, their town slogan is "Keep Austin Weird." That said, walking down the street or going to any kind of festival here will have you encountering all sorts of different looks. There will be people who look like they just transported here from Woodstock all the way to people who look like they just stepped off of Rodeo Drive. It's really common to see the long skirts here, denim or otherwise. Of course, it's also common to see shorts with the booty hanging out the back, as well.
You rarely see teenage or young girls wearing long denim skirts, especially with polo shirts which is what the Duggar's usually wear. Haven't seen any of them wearing fashionable maxi dresses, yet.