Over in the UK, more kids can identify Yoda than they can an oak leaf or a magpie. I'd be quite surprised if the same weren't true for the US as well.
In reality, this isn't surprising. It's not a matter of, "the virtual world ... winning." I strongly suspect that about the same number of kids could also identify Paris Hilton, and other people that aren't at all important in their lives. We're programmed to remember people (or in this case anthropomorphized aliens) much better than mundane objects.
But we'll just let the biologists have their good cry over it. There there. We still love you even if you can't defeat a Dark Lord of the Sith.