The problems the Wii had were deeper rooted than game enthusiasts realized I think.
The general public didn't view the Wii as a normal game console, so the idea of a "Wii 2" (like a "Playstation 2" successor) didn't even make sense to a lot of people.
For example, a lot of people thought the Wii was a total potato hardware wise. I remember knowing my friend was a fan of the Fatal Frame series and an owner of the Wii (mainly for Wii Sports + Wii Fit) I told him there was a Fatal Frame coming to Wii and he paused and said "can the Wii even run Fatal Frame?".
Like I had to explain to him that actually the Wii was more powerful than the original XBox that he had for Fatal Frame.
People don't understand how damaging in some ways the view of the Wii as a casualware machine (even for people who liked casualware games) was ... it become so entrenched with the Wii brand that people didn't take it seriously as a normal game platform and concepts like a "Wii 2" (Wii successor) was confusing to people in the sense that "why do you need a Wii 2? Wii's graphics are supposed to suck, you don't need graphics for Wii Sports and Just Dance" was the thought process of more people than I think Nintendo would want to admit.
The Wii brand in effect eventually became a massive liability. If the Switch was the same exact concept + hardware, but Nintendo called it "Wii Go" or "Wii 3" or whatever ... it would not be selling anywhere near as well, the "Wii" part of it was a massive turn off.