I think it's a really smart strategy. They avoided the raw-power hardware arms race and are thriving because of it.
It seems like Nintendo picked up on what makes video games so fun early on while a lot of studios struggle with it even today: The gameplay comes first and it has to be fun. Art/style comes next, then way down the list is graphics. Graphics are the only thing about a video game that get worse with time. If you focus on making fun games that have a distinct style, they will remain fun forever. Importantly to a corporation, they also remain sellable forever.
Nobody talks about crysis 1 anymore, but people definitely talk about wind waker.