In the wake of Nintendo's problems with the Wii-U and slow path to profitability for the 3DS, I've heard a lot of people talking about how they should get out of the console business and focus on their IPs that still have strong followings.
Beyond having a few great franchises in their favor, one thing I think Nintendo has always been ahead of everyone else on is controller design. The original gamepad basically killed every other type of controller that was available at the time the NES was released, especially the 4-directional, single-button joystics of the Atari. The N64 introduced the analog stick and force feedback and the Wii was the first successful motion controller. While I'm no fan of motion controls, I don't think MS and Sony would have even tried to make things like Kinect, Move or the Wavebird without the existence of the Wii Remote. The DS got people playing with touchscreens before other handheld devices could really play games well.
Sure Nintendo could probably continue to thrive on IP alone, but I think this is one area where the industry would lose out if they ever get out of hardware manufacture. One possibility I think could work though, is if Nintendo was able to continue to build controllers like the Wii-U controller and license them to MS, Sony and other console makers in the future. They could play the games that are native to those systems and have special content that the games could push to the touchscreen if they detect that you are using a Wii-U controller, but they could also have their own app store that sells games through Nintendo that can only be played on the controller itself.
There are changes that would have to be made to the other consoles to make this work and I'm sure their development is way too far along to start incorporating the hardware that would be necessary to turn an XBOX or PS4 into a Wii-U controller base station. It would also conflict with MS's SmartGlass plans and Sony's plans for the Vita, but I think there could be an interesting future for Nintendo to become a console/handheld-only manufacturer and provide components and dev kits to any console maker or game publisher that wants to to connect with their products.