No, good games on the Wii U sold well. Mario Kart 8 sold great, same with games like 3D World, Splatoon, Mario Maker, even core/more niche titles like Pikmin 3 found success on the Wii U. Saying nearly everything bombed on the Wii U is a misnomer. If Color Splash was game that resonated with the core Wii U base more it would have sold well.
I knew you'd try to pull these kinds of misguided technicalities, which is exactly why I said "
almost everything." But let's address the meat of your point.
It's all relative. First of all, I already pointed out that Color Splash released at the tail end of the Wii U's lifespan, when the console was all but dead. Second of all, you think that if a critically acclaimed Paper Mario released on Wii U around the same time, it somehow would've sold similarly to the titles you listed? This is completely unfounded. Even TTYD "only" sold 1.91m on a ~22m install base, i.e. less than 10%. What kind of fantasy world are we living in where Paper Mario manages to sell 20%+ of a console's install base?
And before you say that Color Splash should've sold at least about as well as TTYD all other things equal - no. As I said, Wii U was on life support at that point. And not every single "core" user bought a Wii U by the way, we see that even here on Fami. Plenty of games that sold poorly on Wii U went on to crush those numbers when ported to Switch. TTYD would've sold worse if it released in Color Splash's place and Color Splash would've sold better if it released in TTYD's place.
Because the core fans are frequently more in-tune with the issues of the series than casual fans. Do you not think Paper Mario would sell better and receive more critical acclaim if they listened to the core fans and went back to the RPG formula? Not that there aren't lessons to be learned from the new games, I agree about you with TOK's overworld being the best in the series! But the open critic scores for SS/CS/TOK are lower than the original games for a reason.
Nintendo listened to the core Zelda fans after Skyward Sword received backlash for being too linear and it resulted in the best sell games in franchise history and critical acclaim.
Once again you miss my point entirely. You say more in tune with the "issues" of the series as if the issues are objective, when they're NOT. The only thing TTYD fans are in tune with is their own taste.
Do I think Paper Mario going back to its RPG formula will suddenly make it blow up in sales? Or that going back to its RPG formula inherently means it will be critically acclaimed? No, I really don't. I think TTYD has the chance to outsell TOK, but it won't be by some monumental amount. And I chalk TTYD's quality down to its clever and outside the box scenario writing more than anything, not its gameplay.
Nintendo didn't listen to "core" Zelda fans, they listened to industry trends. Which include the feelings of "mainstream" gamers you're so desperate to believe mean nothing, by the way! It's not like prior 3D Zeldas were significantly more open-ended than Skyward Sword, at least not in any meaningful ways. But I already understand that "core" = things you like/agree with/help your point and "casual" = things you dislike/disagree with/hurt your point, so there's nothing to discuss here really.
I think you're in the majority opinion with core fans saying SV are the best games since B2W2. I was referring to the frequent criticism from core fans from the 6th gen onward that the games were making bad game design decisions. Stuff like the lack of post game content and simplification of the overworlds/routes. Some of that was addressed in SV, that game was mainly derided for the visual and polish issues.
That said I think the core fans were completely right with their criticisms from gens 6-8. They were definitely more in-tune with the issues of the series than the casual fans buying the games enmasse regardless of quality.
Bad game design decisions =/= game design decisions "core" fans don't like. I happen to agree with those criticisms by the way, but to pretend that more post game content or more complex route designs are an objective measure of quality is asinine. I simply accept that the developer's goals and focus changed, and that it does not align as well with what I am personally looking for out of a Pokémon game, but I don't go around calling gens 6-8 objectively bad.
In fact you're contradicting yourself here, because Scarlet and Violet moved even further away from the design ethos of gens 1-5, yet you agree that they're the best games since B2W2? Why, it's almost as if games should be judged on their own merits and how successfully they achieved what they were going for, rather than comparing apples to oranges with a blanket "A is better than B always, forever and ever amen"