TLDR: Nintendo fans won't allow Nintendo to create new IP's and ignore 3rd party on Nintendo consoles.
We all know that the Wii U has been a failure by Nintendo sale standards. With that said, many blame Nintendo for this issue. I mean, who else is to blame? The droughts seem to be endless & the marketing is piss poor.
I personally think that is just an excuse. The people who care about video games (even just a little) know what a Wii U is. This is a big market that is simply ignoring it. The droughts are because of the lack of 3rd party support which is both Nintendo's & the fan bases fault.
losing 3rd party is Nintendo's fault because they decided to release a weaker system as well as a funky controller. This makes it difficult to port things over. They are basically asking 3rd parties to use extra time and money in order to make it Wii U friendly. Some Nintendo fans don't want to buy a 3rd party game because they believe anything other than Nintendo isn't quality enough to deserve their money. As for the ones who do buy 3rd party? Many would rather buy them for one of the other systems / PC because of the graphics increase. So, really, both are to blame here.
Now, another big issue with Nintendo that I've noticed by buying a PS is the lack of new IP's. Sure, they have a decent amount of new eShop IP's but they will go unnoticed on store shelves and will never be seen by the average non-Wii U gamer. They need new IP's that will get public attention. So, why doesn't Nintendo make too many new IP's? The core Nintendo fans won't let them. Every year fans ask them about the next Mario, or Zelda, or Metroid and so on. Retro for example, should be making a new IP but you know as well as I do that if Metroid isn't shown, fans will be disappointed. Fans don't want a new IP, they'd rather take a new entry in a comfortable series. This is fine but is hurting Nintendo's chances in bringing in new fans.