Nintendo has had practically no effect on Sony and MS since the beginning and since the Wii; the same can be said in Nintendo's favor. Regardless of what Nintendo does for the 9th gen, it is unlikely to cause harm to the One or PS4.
I believe that Nintendo will chase after a more pronounced market again in the 9th gen, further removing the chance for possible dents they may cause in the sales of other consoles with different demographics.







