We're not saying that the Xbox One and Kinect are not worth their $499 price tag. They definitely are. But the PS4's $399 price tag certainly looks more attractive to your average buyer, especially someone who's on the fence about which console to get.
The inclusion of Kinect with every Xbox One is what drove the price up, and the Xbox One will probably ultimately benefit from users having a more universal experience. Everyone will have access to Kinect, and that's a good thing for gamers and developers. But the cost up front is higher.