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.
I certainly agree Nintendo could have used the money to keep sw support, just that op thinks of hw support being cut to early when actually sw was the problem.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"
Azzanation: "PS5 wouldn't sold out at launch without scalpers."