It would mean more than that. The new hardware would have to be designed so the old content could run on it. They would have to take an approach more in tune with Android, iOS or Windows, where the hardware is abstracted by the OS so old apps/games would work on future devices.
Nintendo is not an OS company, so it is an area they would have to bring in partners and invest a lot of R&D money, time, and staff to accomplish.
At the moment, Wii - Wii U was a big change in architecture. Like moving from iOS to Android.
With their Handheld and Home Console designers and researchers working together as one department, there is a chance this could happen. A decent hypervisor, and driver model, and a move to something like an X86 architecture would be pretty much essential, but that does not seem as feasible for the handheld side.
The very way they make software and consoles would have to change, so it will require time, and would most likely not fully happen until the next consoles are released. at least 2 years minimum.