Gnome is also avoiding the reality that any given user only uses
a
tiny fraction of the applications on a machine. The Start Menu on
Windows can get to be a godawful mess, but at least you can drop icons
onto the start button so you can always find your top five
applications. People really like the ability to look up the last ten
apps they ran on Mac OS X, and this largely makes up for the miserable
state of the Applications directory.
Someone has actually proposed the sort of thing you're looking for on
planet gnome [1] a couple of days ago.
You can argue for it with Gnome developers on their desktop-devel list
it you're really interested in it.
[1].
http://blogs.gnome.org/view/michiels/2005/10/31/0