Not sure where the benefit lies. A concept with a portable, technologically weaker NX and a home console NX would make it more complicated and expensive for developers. They'd need to optimise their games for two systems. How many studios have done that with new 3DS or DSi? Not particularly many.
And Iwata said a lot, half of that was wishful thinking. At this point, it's better to ignore his words - or do you also believe that Wii U will get software support once NX launched? Kimishima's words would fit into the hybrid line - it's neither a successor to 3DS or Wii U, it's a mix of both.
Official, separate successors to 3DS and Wii U would still be possible. That would just completely destroy the advantages Nintendo would be seeking with a hybrid as separate game development would be needed once again. Unless those "separate" successors are also NX systems. But then what's the advantage of releasing such systems when there's already a low cost hybrid?
No, it's not best to ignore what Iwata said, because Nintendo's continued strategy for the NX (and the overall future of Nintendo) is based on what Iwata has said, as Kimishima has already made very clear by now.
Anyway, I could just as easily point out the confusion for consumers in Apple's lineup, but ultimately it works out for Apple because they unify their products with a cohesive OS across all Apple devices. Again, Iwata has expressed that this is the direction that Nintendo is headed in.
At a base minimum, some developers could design games for the NX OS as a platform and not specifically for one device, while other developers could do the opposite. The choice would be left up to the developers.
As for the purpose of multiple SKUs, you could ask the same question about all the different versions of the DS and 3DS on the market. They all have their own differentiating factors and it's good to give consumers options.
So we're back at more consoles are in development? Because that would make total sense. More R&D costs when investors are still waiting for that magical fiscal year with Nintendo-like profits. Totally logical.
At least my comments are based on evidence that comes directly from Nintendo instead of some warped logic about what armchair analysts think Nintendo SHOULD be doing.