What Harry Potter does not have, or will never have, is the sheer quantity of products attached to it. Star Wars stayed in the popular imagination because of toys, novels, collectables and all the other products attached to it. Disney has done something similar with its Princesses line--the Disney movies have definitely had a larger cultural impact than Star Wars. The only other comparable movie franchise (in the sense of spin off products and cultural impact) is The Wizard of Oz.
What Star Wars has going for it is that it goes far beyond the Science Fiction genre that most of us here on this board are so wrapped up in.