I don't overly agree that Nintendo stagnated their hardware like Apple has with the Mac hardware. Nintendo's "problem" was that their hardware was considered too radical...
lolwtf. If anything, Nintendo consoles are the most anti-radical consoles out there. They're by a long margin the unbeaten kings of hardware stagnation.
Allow me to demonstrate this with their handheld consoles.
Their handheld consoles started with the Game Boy in 1989. 4.19 MHz cpu, 160x144 pixels screen in black&white. It turned out to be a great success. This lead to Nintendo doing nothing for the next nine years.
Nine years later, in 1998: "Game Boy sales are receding a bit, shouldn't we release something new?" "Uhh, well... I know, let's re-release the Game Boy with a color screen. We'll name it... uhh..." *long pause* "Game Boy Color!"
A truly innovative name for a truly innovative device. Same cpu, same resolution, but up to 52 colors on screen now. Amazing. And it took them only nine years to do that.
However, the harsh reality that this wasn't quite enough eventually penetrated the thick skulls at Nintendo, so three years later, in 2001, they released the Game Boy Advance. As they had been unable to come up with anything original, they had just copied the design of Sega's Game Gear, while avoiding its mistakes (like massive weight due to 6 batteries, while still having poor battery life). Again, such innovation! Cpu speed had increased to a whopping 16 MHz, while the resolution had increased horizontally to 240x160.
Again, this turned out to be not quite enough, so they decided to bury the Game Boy line and try to come up with something at least a little bit innovative. In 2004, out came the Nintendo DS. Besides trivial stuff like a tiny resolution upgrade to 256x192 or a cpu upgrade to a full 67 MHz, they added a second screen, and gave one of the screen touch capabilities.
Once again thanks to the help of Pokemon, this proved successful, so Nintendo did the same thing they did after the Game Boy, namely nothing. Only this time, it took Nintendo just 7 years instead of 9 to awake from their idle slumber. In 2011, they brought the Nintendo 3DS. As with the Game Boy Color, it saw only little updates. An analog controller was added, the resolution went on one screen to 400x240 with stereoscopic capabilities, and the cpu went to an amazing 268 MHz.
Just for comparison, some time later in 2011 Sony released the PS Vita. It features a Cortex A9 with up to 2 GHz, a half GB Ram (four times as much as the 3DS) and a resolution of 960x544 on a 5" multi-touch Oled screen (3DS is just 3" and single-touch) powered by a quad-core PowerVR SGX543MP4. If that sounds familiar to some, it's pretty much the same hardware that's in the iPad 2, see
here.
However, once again they're faced with the realisation that the slightly updated 2004 hardware of the 3DS can only do so much, and even Pokemon isn't a panacea, as the well is slowly drying up. So they've now begrudgingly and teeth-gnashingly opened up their franchise, with Pokemon Go on the mobile platform, as well as their other big hit, Mario, coming soon. They've certainly only done this as a last resort, since they didn't have any other options left to stay profitable.
The other problem Nintendo faces is the perception that they only make games for children...
They'll survive with their 1st party titles, but for some people that's not enough to own their consoles, hence the Wii U selling well below even the poor-performing GameCube.
That's true, in fact they're (almost) only releasing children games.
Miyamoto is the ****, but Nintendo continues to block third parties from developing good games on their systems so they can sell more of their own proprietary games for maximum profit sans licensing fees. This generates cash in the short run but alienates large populations of gamers and developers in the long run. They've been doing this trash for years.
Indeed, that's one reason why there aren't much third party titles. The other one being that there are only few third parties who really want to develop for Nintendo platforms and their seriously outdated, not to say antique hardware.
The NX (possibly Nintendo Duo according to recent rumors) will decide much of Nintendo's future, as another failure on the home console front may relegate them completely to handheld gaming, which is a market slowly being taken over by smartphones.
If we look at Nintendo's upgrade history above, let me make a NX forecast:
Cpu will be a Mediatek running at 0.5 GHz (perhaps even 1 GHz, if they really mean business), resolution will be upgraded to 640x480, Ram will be upgraded to 0,5 GB. Screen will finally gain multi-touch, but will be single screen, since they still want to make profit from the 3DS from people wanting to play 3DS games.
Nintendo knows their days are numbered within their current business model. It looks like they want a piece of the Apple pie in some capacity, especially considering their willingness to release a Mario game on iOS. Both parties could derive enormous profit from collaboration on a larger scale, but time will tell.
They're only releasing Pokemon and Mario, their strongest titles, on the mobile market, because they have a hunch that the NX (most likely specs see above) might flounder badly, so they're doing this as a last resort to stay profitable.