People buying Nintendo I suspect do it for nostalgia, as I have never owned a Nintendo product and have zero interest in their games I am not qualified to speak about their games, other than they do not interest me, never have and most likely never will.
And I should mention that Nintendo has a sub 1% marketshare in DK, so I guess culture/geography is another big part of it.
It has been more than a decade since I last saw Nintendo unit IRL and around 2 decades since I dropped their controller in a "Yuck" moment aka touched one