I've talked about this with my friends before and I think it has to do with the defining culture of the 2010's, and that my friend, I believe is so called "hipster culture". Now I'm a Junior in high school, some of you may be in college or a bit older than that as well, so as any of you read this think of the people around you or your kids and maybe just those you walk past on the street or see on the television, but I'd first point to fashion, look at the way people dress now, what's in style now and was in style for the previous years were all offshoots of certain aspects of hipster culture, whether it be flannel then or colorful floral shirts now,look at even one of the most popular haircuts now, the undercut, which was only largely worn by "hipster" circles not only 3 years ago. To girls wearing floral sundresses then too them wearing some denim overalls with a shirt maybe or even now rompers, all of this is clothing I guarantee we would call hipster just maybe 2-3 years ago. Because such "hipster culture" is breaking into the mainstream, it sure follows suit that music is now too, Walk the Moon falls under the Indie, or Indie dance spectrum I'd say, and there is no doubt that a large amount of hipster or indie music and culture are inspired by a large variety of retro and vintage sounds and as mentioned earlier, attire as well. many good examples are listed above and we can even look to the new music genres that formed in these years. Vaporwave, chill wave, and so on are great examples of this. Another great example of course is again "indie" music, which I feel covers a broad spectrum of a broad type of sound, indie music definitely holds many elements and really shouldn't be called all under the same genre I feel, but this may be just how they are changing or adapting to the more prominent culture in the "hipster" realm, for instance you can look too arcade fire back in the early 2000's then look at them now, their sound is radically different with an 80's sort of funk.