The desktop doesn't fit into a hierarchy very well. It feels like it ought to be the "root" of your computer, but it's always really a folder in the user's home directory. In Windows it's even more confusing since they put "My Computer" and the drives under the desktop, which is really in your home folder...
It would work if the desktop WAS your home root, but then you can lose files simply because they're covered up with windows. They could let you open the desktop again in a separate window like current OSes do, but I'm a proponent of the Spatial file manager[0] so I think that would be confusing in other ways. Also some people (me) object to the clutter :)
Lose in the sense where the user comes to me and says "I lost my file!" and I move the window aside and there it is. The same way people "lose" their files by saving them in the wrong folder.
