One of the biggest mistakes of the WiiU was the name, or rather the marketing of the name. They wanted it to sound like a sequel to the Wii, but for casual Wii gamers it was totally confusing. And for a lot of others too.
One of my girlfriends called me up one day for advise, asking me whether she should buy a WiiU. But she thought it was just an accessory of sorts? Totally confusing conversation we had. I told her "no no no it has HD graphics? you know? not fugly as crap?" That was years back. She knows the difference now, as she greatly enjoys Yoshi's Woolly World on it. =).
So. Two other friends I consider kind of semi-hardcore gamers were over two weeks back; they have a giant private cinema set up next to their living room, for watching movies and playing games. They obvs own the latest in Xboxes and Ps4s. So they were over, and asked me "what is THAT?" when they saw the WiiU pad lying arounnd randomly on my couch somewhere between all the Wiimotes and Gamecube Controllers Wii White edition japanese imports with long cables. I said "Oh just WiiU, you know? Never seen it?" and ignored it. Later on, the other one asked me, "what is that device?" Pointing at the *thing* between my Denon sound system and my Switch. So I said "Yeah that is the actual WiiU?" and he asked, "Doesn't it have ugly graphics?" So at this point I was annoyed and suggested to play some. They were kind of blown away by Splatoon and Mario 3D World, and immediately wanted to buy. So that is the epic marketing fail Nintendo made in a name, I think. People didn't get it.