In order to preserve immersion But in more “serious” contexts, realism was still very limited.
One notable exception being the glass “Web 2.0 style” buttons inherited from the early versions of Mac OS X.
As Loren Brichter (of Tweetie & Letterpress fame) pointed out in a recent interview I believe both the realism trend and the recent backlash against it can be traced back to a single product: the i Phone.
Before the i Phone, realism in user interface was unusual, with the exception of video games.
The i Phone's large touch targets requirements opened the door to showing less on the screen, but doing more with it.