So with the really good game lineup the WiiU actually had, I wonder why even Nintendo fans were so averse to buying it.
Surely they couldn't have foreseen Nintendo re-releasing all the major games just a few years later on a new system.
1) marketing was bad -> first trailer never showed the console, everyone thought for years Wii U was an accessory for the Wii. Nintendo also didn't push it much after launch.
2) The concept wasn't very appealing -> "you can play the games off the TV" great, except you can't move from your couch.
3) the timing was bad -> a year before next gen consoles with an hardware that was even less powerful than a PS3.
4) Pricing was bad given the hardware -> they lost that impulse buy appeal the Wii had with its insane launch price of 249.
5) Launch line-up was decent to good but it had no Breath of the Wild. The great games came out later with big delays.
6) developers went out on trashing the system few months after launch because it wasn't very powerful and a nightmare to develop.
7) The 2 screens mania that was a thing at the time, it didn't last very long.
8) Nintendo coming from the huge successes of Wii and DS was a bit more pretentious (almost arrogant) than today.
9) it missed many major mainline entries among their franchises: no Metroid, no mainline Animal Crossing, no Fire Emblem,...
10) the controllers situation was a mess: certain games required the Wiimote, others the balance board, the pro controller wasn't supported in all games,...
and many other reasons.