I think Nintendo (and Microsoft and Sony) are just facing the reality that this generation is coming close to the end. Between the three manufacturers we have sold about 90% as many consoles this generation as were sold in the previous generation, and early in 2011 we will have sold more systems in this generation than the previous generation. While there are (probably) more people who have bought multiple systems, and there will have been some people who were "pulled into" the console market, we're rapidly approaching a point where everyone who is willing to spend more than $100/$150 on a console will own every console that they want to own. The only thing that can really change this is if there is a major reason introduced to buy a system that people don't own; but I have seen nothing on the horizon for any console manufacturer which would (truly) qualify for that.
Unless something drastic changes, I would expect hardware sales to decline across the board until the next generation of systems starts to be released.
