If you think about productivity, you can’t help but think that having the default state of your computer being an image with a few icons on it is less than stellar. For opening files, it will never be tidy enough to give you access to all you need, you need a launcher or a folder structure, meaning the desktop is bad at this. For opening apps, having visual shortcuts on the desktop is a duplicate of whatever panel or launcher you have.
Ah, OpenDoc. It was a good start, back in the 90s, and now is seen as an impossible pipedream. Ah well.