You'd be hard pressed to say Nintendo is ever doomed for all the reasons you stated and more, but they do seem to be going through more and more bad phases with their hardware since the 2000, to deny just how dire the competitiveness of Nintendo through Gen6 and Gen8 was can be an issue, particularly if their means of addressing any long term concerns is by continuously gimmicking their systems out, which doesn't always hit, ala WiiU. With portable platforms on the decrease as well, I wonder how long the Switch will last on it's current success.
There could be a time in the not to distant future where Nintendo become solely publishers of their IP's, not in the sorry way it happened to Sega, I imagine were it to happen for Nintendo it would be on their terms.
Playstation gaming for 18 years this 2012 
