If they decide to continue trying to juggle two platforms rather than just focusing on the NX, they won't get out of the hole they're currently in. Microsoft and Sony have the luxury of just focusing on one platform respectively, Nintendo needs to start doing the same.

Nintendo isnt doomed until they start posting consecutive annual losses and their first party software starts selling poorly.

Pokemon X/Y-14.70 million
Mario Kart 7-13.26 million
Pokemon OR/AS-11.84 million
Super Mario 3D Land-10.73 million
New Super Mario Bros 2-10.25 million
Animal Crossing: New Leaf-10.00 million
Super Smash Bros 3DS-8.12 million
Mario Kart 8-7.50 million
New Super Mario Bros U-5.19 million
Nintendo Land-5.07 million
Tomodachi Life-4.98 million
Super Mario 3D World-4.82 million
Luigi's Mansion: Dark Moon-4.82 million
Super Smash Bros Wii U-4.80 million
Splatoon-4.27 million
Legend of Zelda: Ocarina of Time 3D-4.04 million
Nintendogs+Cats-3.96 million
Super Mario Maker-3.52 million

I think 3 gens in a row of a Wii U happening.

But the software sales for some Wii U games are surprising.

Many people in this thread fail to realize - Nintendo is a business. They're in it to make money. What could cause Nintendo to exit the console business? Simple. The investment in consoles becomes no longer justifiable. If the board of directors feel that Nintendo is better off investing their money in other endeavors in order to make greater profits, that's what they'll do.

It's not a matter of making money. It's a matter of making enough money for the board of directors to remain confident that producing consoles is the most profitable direction for Nintendo to take.