Puggo - Jar Jar's Yoda said:

Geez, that's like saying if Leonardo DaVinci didn't paint the Mona Lisa, somebody else would have. You can't really believe this, can you?

No, but someone else would have painted an equally admired piece of work to stand the test of time. Or, in the absence of one piece of art another would naturally take its place in terms of importance and reverence.

If SW didn't exist people wouldn't be able to miss it. Something else would be as widely loved in its place.