Could you go back to using a non "flat" UI?

iOS 7, Windows Phone 8, Android 4.4. All the main mobile OS have moved to a more flat design. Could ever go back to the way things were before? Personally I love flat design after using Windows Phone 7.5 for two years, Windows 8 for almost one year. I am currently using iOS 7 and so far love what they have done with it.