I think to a certain extent we already had Movie OS in the early 00s / late 90s when all kinds of apps were skinned. People would make all kinds of baroque skins that looked like they came out of movies, that acted much like this, but you know what? They were cluttered and hard to use.

Who remembers Winamp 3, with its fancy skins[1]. I know I breathed a sigh of relief when iTunes with its simple, yet highly functional, interface came out.

1. As an example: http://www.thg.ru/technews/images/winamp_skin-270206.jpg