For me, the Wii U is and isn't a failure. It's a mixture of both. I'll first list why I feel that the Wii U IS a failure:
- Nintendo marketed the console poorly
- Little to no Third Party support
- People see the console as a 7th Generation console, instead of an 8th Generation console
- People think the Wii U is an add-on for the Wii
- The console is much weaker in terms of horsepower compared to the PS4, XBox One and PC
- The console revolves around a controller gimmick (Gamepad), repeating the Wii (Wii Remote Motion Control)
- People label the Wii U as the GameCube 2.0 or Wii 2.0
Now let me list why I feel the Wii U is NOT a failure
- Great First and Second Party titles available and coming out that will convince people to buy the Wii U
- The console is cheaper than the PS4 and XBox One, so it's more affordable
- Free Online
- It's backwards compatible with Wii games and you can transfer your data from your Wii to your Wii U
- It's had great reliability so far; people have been having a few issues with their PS4, XBox One and PC
That's what I can think of as of now.