AppleTV is getting a software update too. Don't confuse the iOS 4 AppleTV with the iOS 5 AppleTV. Apple isn't dumb. Like Steve said, they build stuff they want to use themselves. I'm sure they've thought of this.
I don't know much about retail, but I don't think that's the way it works. If it did, you'd see the same products priced differently in different outlets. Instead, what we usually see is a fixed retail price.