Reggie Fils-Aime, chief marketing officer for Nintendo of America, said publishers of games for its Wii console needed to sell one million units of a game to turn a profit. He said that was a lower threshold than for the other consoles. Only 16 out of 486 games for Nintendo Wii game machines have sold more than one million units as of March 1, according to NPD, which tracks the sales of consumer products. (Nine of the best sellers are made by Nintendo.)
From this New York Times article. http://www.nytimes.com/2009/03/30/technology/30game.html?_r=3&hpw
Pretty interesting that even on Wii it seems pretty tough to make money, this also means the amount needed to break even on HD consoles must be even higher for their average game.