Tbh I can see what the OP means, Nintendo in previous gens made statements a long the lines of we'll balance our focus and still support the DS even though the Wii is about to be released etc... The way this statement is worded hints that both 3DS and Wii U will be replaced by NX as the's no reason to mention both handheld and console if only one is being replaced.
The secrecy over the NX also highlights this, before Nintendo would just straight up say it's a handheld or console when they confirmed a platform is on the way but here the silence over what type of hardware it is suggests it may in fact be what's been speculated.