Because Pathfinder is a variant of 3.5E D&D with all of the same tropes - D&D races, classes, monsters, monsters, magic items, etc, whereas Star Wars is a science fiction (or science fantasy) game with completely different tropes. The division seems pretty clear to me.
As for your last sentence, I'm not sure I agree with you but that is an entirely different conversation. You could very easily change "Pathfinder" to "D&D 3.75" and not miss a beat.
O Rly? And what data might that be?I think the data indicates that the overwhelming majority of players over the history of the hobby are like me. When they stop playing D&D, they stop roleplaying.