And why should it continue to be that way? I don't think it should really, and Nintendo should try to push more for those games on their consoles. And I'm not looking at it as "Why people should choose Nintendo over PS4/XBO", but why people should choose Nintendo. Perhaps portability of the Switch is the way to go, although it'll be lacking some big games from other consoles, or maybe a standard console that can play those multiplatform games and Nintendo games is. I don't know, and that's where I'm torn. I'm not really saying either one is right.
Getting those games doesn't mean anything if people don't buy them, Gamecube had solid 3rd party support and Wii U did as well initially and it did almost nothing for them and are Nintendo's two worst selling consoles.
In order for those games to sell well and move hardware for Nintendo, they need to steal the audience for those games away from PS/XB so I ask again, what will cause existing and prospective PS4/XBO owners to get a similar Nintendo console?
If you can't come up with a reason why these people would choose such a device than you have no reason to think they will.
When the herd loses its way, the shepard must kill the bull that leads them astray.