Top 20 selling apps in the Apple store[1]. A quick perusal will convince most people. I didn't check all of them, but I saw ONE which used standard display components at all in the screenshots (the guitar one), and it only does so for setting preferences.

Think it's coincidence?

[1] : http://www.macrumors.com/c.php?u=http%3A%2F%2Fitunes.apple.c...

edit: and again. Pixel art. 3D / vector art isn't the only kind, you know. Just look at any favicon, for example.