1. Third parties are biased against Nintendo
There's the belief that third parties would include every platform on Earth into the mix as long as the platform in question offers their demanded specifications. A prerequisite for this belief is the assumption that no third party would pull the line "We do not believe that there is an audience for our games." and forego giving support to Nintendo. This is an unsolvable problem for Nintendo, because the only realistic solutions would be to either pay off third parties for ports (thus ruining profitability) or build an audience for such games themselves which would lead into another commonly used excuse ("Only Nintendo games sell on Nintendo systems."), because consumers' expectations for quality and polish would be raised to levels that third parties are unable/unwilling to match.
This is precisely why I want to see Nintendo partner with certain specific studios to bring their level of quality to genres and styles of games that are currently popular on the other platforms. I honestly think that a WWII FPS shooter with a Nintendo spin would actually be a massively popular title. If you think I just mean an "army shooter", think again - I mean WWII shooter, the genre that was popular 7-8 years ago and fell out of favour, with the "modern shooter" taking its place.
Publishers proclaim that they can't compete with Nintendo when they barely compete in the same genres? Let's see what happens when Nintendo decides to show them how it's done in the genres that are their bread and butter.