That's how it always goes at console launches. The hardware sells in small numbers, but you keep putting software out there to convince people to make the leap and buy it.
How many 360s had been sold when Gears first came out? 5 million or so? Not exactly a huge number. And yet that game became a must-have app, drove hardware sales, and ended up selling over 5 million on its own. That's how its always gone in the first year of a console launch, and developers are idiots if they think it will every go otherwise.
I'm talking about software. Look up sales figures for AAA style shooters, and tell me about the disparity between the Wii/360/PS3 and how devs should be using time and money to optimize for the Wii/Wii U.