Gamasutra quotes Epic Games' CEO Tim Sweeney from GDC Taipei:
The most profitable game we've ever made, in terms of man years invested versus revenue, is actually Infinity Blade. Its more profitable than Gears of War.
Say it ain't so... Infinity Blade was sold at a lesser price and thus sold more copies. Infinity Blade also had a much, much smaller investment as noted in the keynote, as it is a much smaller game. This raises an interesting question: Can these economics be applied to the traditional large-scale games of the console market or is that market simply not large enough?
Sweeney seems to think the answer instead lies in free-to-play games. (Its interesting that Infinity Blade 1 and 2 are not free-to-play.)