Ninti doesnt need Hardware developers but a management that cares for thirds.
Wii U is a hardware tailored for Nintendos needs and around the gamepad.
That might have worked if Wii U had been a major success. With a Wii like install base even third party exclusives might have sold enough. Or cut down versions like the Wii CoDs.
It just wasn't a success nor will it be.
By the way, I have more Wii U than X One games. So it's not that I hate it. It's just underpowered compared to other devices.