Mobile games, like Pokemon Go and Mario Run, are a great way for Nintendo to market their characters, advertise for new games/consoles, etc but should never be the full focus of the games. Nintendo and its developers do well when they focus on innovative gameplay of their core series and the best known characters.
Look what Pokemon Go did for the New 3DSXL and Gen VI Pokemon games - sales went up, and it's the 20th anniversary of the franchise, and there's a new gen coming out which got people excited. It definitely made me pine for the older games and next thing you know, I was at GameStop buying and 3DSXL, OR and X and putting a deposit on a pre-order for Sun. It works. (Granted, Pokemon Go is a Niantic game, not Nintendo, which the latter only making money off the game residually due to their stake in the Pokemon Company International, but still)
I see Mario Run doing the same thing - promoting and creating excitement for both the platformers on the handhelds and the newer games, like Galaxy, on the home console.
It's great seeing Nintendo finally break into mobile markets and having some cute games for Android or iOS. But I think the company would be foolish to abandon what made them an international household name or characters that prints them money. Glad to see them not listening to Wall Street on this one as well. Especially since cell phones have planned obsolescence of only about six months, whereas the major consoles (Nintendo, Xbox, Playstation) usually plan their consoles to have a market life of 3-4 years before the next gen comes out.