WiiU has surpassed the Dreamcast is the United States.

[thetonestarr]

Wman1996 said:

But what you have to realize is that the Wii U was released in all the major markets at roughly the same time. The Dreamcast had a staggered release. The global market affects the domestic market.

Also that the Dreamcast was discontinued after only a year and a half, while WiiU is coming up on three years.