It's not the fact that the console is underpowered. It has to do with 1 thing:
Money
And the reason why 3rd party publishers see the Xbox One and PS4 as viable gaming machines is because they can ensure DRM.
While this seems so anti-consumerist for that to be the reason for abandoning Nintendo, it makes sense.
If Square Enix's Tomb Raider breaks 3 mil and is considered a failure, there is a showing trend that 3rd party publishers need to make money.
And DRM ensures just a few more dollars that they wouldn't have if they didn't support it.
Nintendo is not going to implement DRM. It never was really an issue for them, and I don't think it ever will be. That being said, now we see why 3rd parties aren't going to support the system. Because they can't make an easy buck.
Sure, Wii U sales need to pick up for a true reason to develop for the console. But studios are going to make excuses as to why they can't develop on Wii U, even if it becomes the best selling console of the generation.
Sure, that may entice some publishers to come back. But in the end, they're always going to find a way to skirt around the subject of supporting the system. They'll make the argument that their games aren't going to be able to sell while competing with Nintendo's first party offerings. When in fact they had this GIANT time window to release these games before Nintendo's heavy hitters.
On top of that, where are we seeing the majority of the 3rd party support for Nintendo? Eastern Publishers.
Western Publishers, on the other hand, seem so engulfed in the corporal and financial aspect of the gaming industry. Western publishers are the biggest proponent of DRM. We see so many cases where the actual development teams working under these publishers had games ready for the Wii U. The fact that EA made CryTek can Crysis 3, or the fact that Rayman was delayed, and that most developers had to come out and apologize to the gamers in some way. Not the publishers, but the developers.
I honestly think this trend will prevail until 3rd parties come crashing under their own weight. AAA Games cost way too much to develop nowadays, and eventually they'll have to resort to "crawling back" to Nintendo.
DRM and all of this corporate mumbo jumbo going on is going to bite the gaming world as we know it in the butt eventually. Eventually it'll get its act together, but it'll be a long time coming.
It's unfortunate for us as Nintendo gamers, but at the same time, it seems to be an inevitable evil in this day and age.
Thoughts. Please let me know if I'm just way out on left field here.