The fact that you have seen only a few number of icons on a Mac simply
means that you have only seen a few programs on a Mac. When a Mac program
creates a new document file, the document file automatically gets the same
icon as other document files created by that same application. Each
application can have its own icon, as well as have one or more icons that
are to be used for the documents created by that application. The point of
an icon on the Mac is to say (for example) "this here is a document created
by MacWrite". If all you use is MacWrite then you will never see more than
two or three icons (not counting system icons).
James Bayless
New Horizons Software, Inc.