When the 3DS went on sale, people said it was expensive. And they were right. For a Nintendo handheld, it seemed pricey, leading to sluggish initial sales. That's why Nintendo cut the handheld's price shortly after its release. Nintendo doesn't want to repeat that same mistake again -- because that mistake ended up being costly (and sucky) for Nintendo!
In an interview with a Japanese newspaper, Nintendo president Satoru Iwata said that he doesn't want gamers to feel like if they waited to buy the Wii U, the console would get cheaper. That sounds like Nintendo will price the Wii U competitively at launch. If so, that would mean that price cuts wouldn't happen until later in the console's lifecycle. So, there you go.