When I think about Nintendo I think about Mario, Zelda, Donkey Kong, Metroid, Smash Bros ETC....I don't think about the Wii, Wii U or switch. The consoles them selves are fine for their game but nothing else. Nintendo should bring there games to everyone and produce them for the Xbox and Playstation. They would make a killing!
Most people who like Nintendo games aren't that much a fan of games you see mainly on Xbox and PS4.
That's why it is good that they make their own consoles for mainly their own games.
I know the Wii U failed miserably but that may happen when you are taking risks. Nintendo has been al about taking risks with their consoles at least for the last 10 years. They try to invent something new and people like it or not. The Wii introduced Motion Controls and succeeded. The Wii U introduced the gamepad and it failed so that didn't work out. The switch also has alot of new functions and it is still hard to get before the new load is sold out.
So although the Wii U failed, they make good consoles and will keep introducing new things that might become revolutionary in the future of consoles. It would be sad if they stopped.