Capcom would have been totally fine with Mega Man in SSBB

[A Black Falcon]

That's true, there are very, very few third-party exclusives now, due to the need to make more money to make back the high development costs of games on those platforms... that's definitely hurting the PS3. But really, it's mostly about momentum... people buy the consoles that are doing well, usually, and hold off on the ones not doing as well. And with the PS3's cheapest model now costing twice the amount of money of the X360's cheapest model...