Well I don't think it's a failure because it didn't generate enough money, I think it's a failure because it a certain class of microtransaction-centric game does brand damage to perhaps the premiere game brand in the world.
Now this is pretty crazy but hear me out.....they could have just not turned the game into microtransactions
How? The target audiences for games like Mario aren't going to suddenly stop liking it because a predatory mobile game exists in the same series.
Maybe Nintendo didn't like the trajectory, or the potential for brand damage to their treasured IP, even if the mobile games weren't even denting the reputation yet.