People have been going back and forth on this for years now. To me it comes down to what niches each company wants to fill. Obviously Nintendo has a long history of family and party games, which lend themselves to in-house multiplayer. MAYBE if Nintendo focused more on online-gaming it would put them in the exact same market as PS4/Xbone and the competition would just be that much worse, but you'd probably have to go into an advance analysis and crunch numbers to really figure that out.
Does anybody here have kids? What do they play? I almost feel like, while children are the target audience, adults who grew up on nintendo are the majority of their customer demographic, and honestly, adults are not going to buy as many video games as kids, especially when most adults are playing on PC through steam and whatnot.