F-Zero X and GX had 30 opponents racing at the same time. But both games were offline. The possibility that nowadays this can be played online with 30 people isn't good enough for Nintendo to make a new game?
This reminds me of Starfox not being made for the Wii, despite it's controls being tailor-made for this particular game.
If "lack of new ideas" is the reason for these, then it's a bullshit excuse. These are called "missed opportunities". Nobody is asking for new ideas, these games are already great.
Look at Mario Kart. There aren't really any "new ideas" ever since Mario Kart 64. All games play the same with some added minor gimmicks. And yet not only they release at least one game per console, they even re-released the same game twice, just so the Switch can have a Mario Kart. Then you have the New Super Mario Bros games. And the Smash Bros games.
So the real excuse should be "it didn't sell as good as Mario Kart or Smash so we can't milk it". But they don't want to say that because it will make them look like a normal, profit driven, greedy company like all the otrhers. Which, again, is normal, nothing wrong with that. But no, they can't have that, they need to sell you the image of the good guys who care about games.
"New ideas" my ass.