There's an interesting article
I found that comments on the recent decline in Wii
sales. Though I agree that there's not a whole lot of first party software coming out for Wii, I don't think the Wii's price or market saturation is the issue here. When Wii's are lining store shelves, I'll agree that everyone who wants a Wii has one, but I know first-hand that that's not the case. I've never seen a Wii in the wild and the employees of stores such as Target and Meijer I talk to always say their Wii supplies are snapped up within an hour of the arrival of the shipment.
I'll agree that $250 is a lot for a Wii, but considering the price of gaming products in general, it's really not as bad as it could be. Sales may be slowing, but not enough that Nintendo needs to panic; I don't expect a price cut from Nintendo until Christmas or early next year.