..because those other archetypes do not have a special set of rules for roleplay and/or advancement.
Actually, those 4 rp'ers don't have the time to devote to recreating the list if we get more peeps who suddenly "discover" TRF and want to play force-users when the very same set of wallflowers who are bitching about the uselessness of the list now suddenly ask (as if it was the most brilliant thought to ever come out of here), "Why don't we have a list of force users?"