Sure, but at the moment people are citing the technical aspects of Natal as unjustified - "It's not worth $150 because it's a couple of cameras." The same argument can be presented for Wii - "it's not worth $200 because it's just a $40 GC, and XB360 is much better value." If this is all consumers were presented with, I doubt many would have bought Wii. However, they were presented with different experiences, and it's there the value proposition comes into effect. The products have a degree of appeal that potential shoppers have to weigh up against its cost. Is this experience worth this price? At the moment we don't know what Natal/Wave's experience is. I hope! If the experience is limb-waggling breakout, it's certainly not worth $150! But if it offers some world-changing experience as yet unshown, it may be people look at the price and think, "it's steep, but man I've gotta have this!" and shell out.
I think you are overlapping your consumer here, to be $150 you have to already have a 360 otherwise it is $300+ (based wholly on rumored pricing). The Wii argument is fallacious considering how many units the GameCube sold and how many the Wii has sold and it also proved that the Wii WAS the better value given how many units it continues to sell; there was no me-too aspect when the Wii launched. What you and Rancid are saying is that "we" are delusional to think that the market that has already purchase a Wii is now primed to drop $300 on a 360++ or you are saying that there is still an untapped mass of consumers that has so far shunned the 360 AND Wii that is primed to purchase the 360++ en masse and with that, I do not concur.
I am under no delusion that my gaming expenditures are considered the norm.