I think the core issue here is that Nintendo is still trying to be experimental in an era where budgets and development cycles really don't allow that.
Mario Kart World, an open world kart racer originally developed for the previous gen console - many players don't think the open world aspect brings enough to the table to justify the whole game built around that. The overwhelming response from players is that MK8 was better.
Pokemon ZA has stripped out all form of strategy, and now you just have to mash buttons as fast as the timers will allow you to coast through the game. There are no more abilities, no more items taking a valuable turn; just hit the button that's not on cooldown. And you can run around now. This game has no competitive legs whatsoever.
As far as public consciousness goes, Mario Kart and Pokemon are pretty big tent pole titles for Nintendo, and yet the response to them has been underwhelming to resentful. People are big mad about having to buy a new console to play these $80 games, and then they are less fun and engaging than the very old games they already own.
What's the solution here? More paint by numbers games that appeal to test audiences? More trend chasing? Unfortunately, it takes so long to develop a game, some of those trends have already come and gone. Lower the price of games to reduce the sting of dissatisfaction? That could help.
I think what Nintendo really needs to do is tap into that war chest and hire more developers. We have these massive, huge IP, the deserve higher development budgets and larger teams to be able to produce higher quality, even experimental games, out faster.
We were promised with the consolidation of Nintendo's consoles, from the Wii U and the 3DS to the Switch, we would get more games. But it feels like the number of games hasn't really increased, in fact, it feels like we have less games overall. Not only is it a huge wait between entries, the quality doesn't seem to be there to make up for it. It's been eleven (11) years between Mario Kart 8's original release and World. If we go 11 years back from 2014, we got Mario Kart Double Dash, Mario Kart DS, Mario Kart Wii, and Mario Kart 7 in the same time we've gotten one new game today.
Maybe this is an HD towns are hard problem. But it sounds like the billion dollar company that sells video games as a business model should figure that out, and it sounds like maybe putting more money into developing these games will go a long way.