While it started beforehand, it was really smartphones and especially the iPhone that gave so many UI guys an excuse to discard all of the studies of the past and start from scratch. "Oh, but it's a touch interface, these lessons are about mouse users, certainly discoverability and clearly differentiating UI elements don't apply anymore. Our users are so smart they will just know that a half swipe from the middle of the object is different than a half swipe from the edge, and they don't have to be told about functionality that is infused at birth now."