This isn't a platform specific thing, it's about bringing Unreal Engine 3 to the entire portable market. (anandtech.com)
I didn't say it would always be the top portable market, I'm only saying there IS a market to begin with. (n4g.com)
But, as you alluded to, I've been anticipating a future where Nintendo all but abandons the home console game in favor of absolute portable market dominance. (gameological.com)