I get now what your point is, Nintendo has been getting far better at selling a wider variety of content these last years than previous generations, they always had an issue when Super Mario or Pokemon outshined every third party on the sales chart, and that always caused a few struggles with their fanbase and other publishers, their perception among 'hardcore' gamers has been huh, mixed when they talk about buying a Nintendo console.
But, every company challenges are different , Mario is one of gamming's greatest icons, they will always care about the plumber and their classic series, its impossible not to, wouldn't be standing were they are today otherwise.a wide variety of gamers young and old, core and casual care about Mario, Pokemon, and now Animal Crossing. They will always develop and publish these games for everyone, they just aren't hardcore exclusive like the other companies lol and that's fine
Still they been trying to push other content, genres and age ratings, all success they are having with third parties today didn't costed them nothing and while their sales data is far more modest than say PlayStation, its getting a lot better because they keep throwing money at third parties, new collaborations,new hardware, advertisement, surprises, actually have been surprising us a lot longtime Nintendo gamers.
Those 2 million of Xenoblade Chronicles was a ton of hard work of publishing multiple games across 3 generations, but they didn't give up on Monolith Soft and kept improving as a publisher, even been willing to go outside their bubble and find developers to work with closely and support, for example Warriors games are a lot different today thanks to Nintendo. Their relationship with Tecmo is very strong, also been taking care of Shin Megami Tensei with Atlus, Monster Hunter with Capcom(spinoff and main), Bayonetta with SEGA after they couldn't afford to, and even smaller niche titles like Deadly Premonition(apparently Switch was the only chance this team had at making a sequel,some time later it came to PC)