Some things they forget:
Nintendo is a Japanese company. They are patient as an elephant. They don't care if they lost one generation of consoles, hey, its just 5 years.
Nintendo is a rich company. Valued billions, having billions in cash reserve. In fact it is one of the richest companies of Japan.
Mario, Zelda, Pokemon etc are the high value IP's which cause people to buy Nintendo hardware.
Nintendo always innovated the consoles, controllers and systems with Sony & MS following their lead.
Compared to Sony and Microsoft Entertainment Nintendo had profitable console generations. MS did not. Sony did not.
Why should they bother about other platforms? Nintendo often enough stated that they do not see MS or Sony as competitors. They merely see bicycles, girls and TV as competition as they steal entertainment time from their consumers.
German article on Krawall.de mirroring my opinion:
http://www.krawall.de/web/Wii_U/special/id,65290/
And a video / Statement with the same position:
http://www.gametrailers.com/videos/uujebd/the-final-bosman-what-about-nintendo-
