The Wii died because there has never been a steady stream of quality games for it. It's yearly lineup was typically dominated by one big 1st party title, an second tier 1st party title, "non-games" and a mix of bad PS2 ports to round out the third party support. It's not like Nintendo's top development teams weren't doing anything for 5+ years. If Nintendo had made sure their various developers were actually releasing shit, who knows, maybe the Wii would still be kicking today.
Instead Nintendo bet the farm on a demographic that now only pulls out their Wiis for Thanksgiving and Christmas parties