I understand that. It's obvious, and it's also not the point. The point is that Razer made so many sacrifices to specialize this laptop that they ought to be able to undercut the MacBook Pro by a lot more than $150.
The use of a dual-core CPU instead of a quad-core CPU should cover most of the cost of the GPU upgrade, which means that either Razer's trying to make a lot more profit per machine than Apple's flagship laptop, or Razer's getting screwed on the cost of a bunch of commodity components.