Doesn't it make more sense to view Nintendo's current dominance as the exception and not the rule? It is, after all, built not at all on the traditional Nintendo formula: storybook adventure games that hide deep mechanics beneath their cheerful façades. Rather, the Wii has sold on the back of low-quality sports sims.
Nintendo has found a profitable niche. But it's nothing at all like the niche they've had for themselves in the past.
This speaks volumes to me. Very little the Wii has done this generation has had the footprint of the traditional Nintendo formula. They are in somewhat uncharted territory as far as I'm concerned. And regardless of your stance on Nintendo/Sony/MS it's tine to admit that Nintendo has indeed found themselves a niche in gaming this generation.
Something very comparable to the niche that Guitar Hero found. This isn't a matter of 'being themselves' it's a matter of catching lightning in a bottle.