Or could it be because of the massive amount of coin that particular franchise can bring it with seemingly the merest mention. You have Lego teaming up with Star Wars, and boom - big money maker. You have Family Guy teaming u-uhh spoofing on Star Wars, and boom- big money maker. I mean, not only do they get to sell that episode on dvd for the season when it comes out, but they're selling it on their own right now.
Pepsi puts Yoda on their cans and sails raise. Fast food place puts crappy representations on "collectible" plastic cups and sales raise. This is one of the largest franchises in the world, quite possibly the biggest movie franchise (why?) in the world, with a huge cult following.
That might have something to do with it. Oh and the whole thing's built on light saber battles and old samurai crap - so yeah, actually kind of fits in.