This means, hypothetically speaking, that NSMBU should have sold at the same pace as NSMBW if there was no fatigue and disinterest of the greater market. Would you agree with this?
It would have to compat the high price entry of the U, as well as the steep price of NSMBU as compared to NSMBW, but it would have more power in and of itself yes. However, I doubt that it would have the same pace as NSMBW. That's why I take the curves with a grain of salt, as I understand there may be more than one thing happening at a time.
Remember back when NSMB released for the DS, it was a big novelty, and the same was true for NSMBW.
A good chunk of the people who bought only Angry Birds aren't interested in full fledge video games and never will so they're not part of Nintendo's potential market.
Did you ask them?