They didn't need to support it at 100% of their dev power. Just enough to justify it being around. Hell, they were swimming in buckets of money back then, they could have paid other studios to keep quality Wii games coming, or just open more studios and let them experiment with the Wii, it's not like they needed to make the system sell at this point.
Opening a new studio is probably the most expensive option for a publisher to do. Especially since you are proposing that these new studios become experts in a soon to be obsolete console.
As for the topic in general, I don't know. It is hard to say. The fundamental issue is that Nintendo just can't support so many consoles at once. You had the 3DS launch in 2011, Wii U launch in 2012, plus trying to support the Wii up through 2012. They were basically trying to support 3 consoles at once. I guess 4 if you count the end of the DS lifecycle (Nintendo published games up through early 2012).
I just hope with the single piece of hardware, generational transitions go more smoothly for Nintendo.
NNID: theRepublic -- Steam ID: theRepublic
3DS - Currently Gaming Like It's 2011 - The Legend of Zelda: Ocarina of Time 3D
PC - Currently Gaming Like It's 2012 - Borderlands 2
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