Dovetailing with Evlar's point, I think it's worth noting that empirical evidence suggests that the games we think of as "casual," with Wii Sports and Wii Fit being headliners, are apparently much more difficult to make than "hardcore" games, contrary to popular belief.
The evidence of this is in the sales figures. Virtually every major publisher is capable of producing multiple "hardcore" hits a year, from the recently venerated EA with Madden and Warhammer to the now loathed Activision with Call of Duty to smaller companies like Epic or Bethesda to Japanese companies like Konami and Capcom. The fact that so many companies of varying sizes, from different cultures and of different backgrounds can all produce games with high review scores and strong sales suggests that it isn't very difficult to make these types of games.
By contrast, virtually no one outside of Nintendo (Activision being the sole exception with Guitar Hero, I think) has been capable of capturing the "casual" demographic in a consist and exceptional manner. This suggests that it is difficult to do: if it were easy, everyone would be doing it. Even Ubisoft, the perpetuator of the Imagine and Petz lines on the DS, has never really seen an exceptional success with any individual game: to my knowledge, none of these games has individually sold more than 5 million, and I'd wager that only a handful have passed 3 million, if that. Their success on the platform comes from sheer volume of SKUs, not from a few SKUs selling enldessly a la Brain Age, Nintendogs, Brain Age 2, and Animal Crossing.
Now, please note that I'm not saying that this makes casual games "better" by some objective standard, I'm simply saying that empirical evidence suggests that it's actually more challenging to produce a big casual hit than it is a big hardcore hit. I'm pointing this out because Omar's argument earlier relies on Microsoft being capable of creating industry driving casual software, and I'd argue it's unlikely that they can, given that almost no one but Nintendo seems capable of doing so.