Leaving the backwards compativility theme aside, I think it can be something related with the move Nintendo did from the Wii to WiiU and adapt it to its home and handheld consoles.
I make this assumption from how the quote ends: "When this happens, home consoles and handheld devices will no longer be completely different, and they will become like brothers in a family of systems." and from my believe that Nintendo will launch a handheld and a home console, not a single device that works as both of them.
So, when they moved from the Wii to the Wii U what they did with the CPU was add 2 extra cores of the same kind (more or less) and use a new GPU that could run the old games with ease. If you mix that with the idea of a handheld and home consoles working as a family, what I think he meant to say was that they will use a single design or architecture across the portable and home consoles, but it will be a scalable design that will allow them to have a hardware solution with modest specs (but small power consumption) for its handheld and then use the same hardware but in more quantity to get a home console with bigger performance.
Think of it as going with an APU design of sorts with a 2 core CPU + 8 GCN "cores" for the GPU for its handheld while going with an APU with an 8 core CPU + 32 GCN "cores" for the GPU. Both systems will use the same kind of CPUs and GPUs thus allowing devs to learn only 1 architecture and using the same tools to develop for both devices, but because of the difference in performance between them (the home console has 4x the CPU and GPU), they are different enough as to not being the same thing and do the same.
Please excuse my bad English.
Former gaming PC: i5-4670k@stock (for now), 16Gb RAM 1600 MHz and a GTX 1070
Current gaming PC: R5-7600, 32GB RAM 6000MT/s (CL30) and a RX 9060XT 16GB
Steam / Live / NNID : jonxiquet Add me if you want, but I'm a single player gamer.

























