ACNH is indeed bigger than SwSh and the most eventful game this year. Probably setting Animal Crossing in a new field of popularity and fame
But it's not true ACNH is the most prolific IP in Nintendo right now not even if we talk about game market only. Firstly because Mario exists and this little guy is the face of dozen of successful games. Second because of Pokemon Go: It grossed almost 900 million USD last year, and well, we're talking about a free mobile game so it's very clear it will gross some hundred of million dollars again this year in the next years
AC is booming, but still having too much space left to grown. As a new fan, I'm excited to see what Nintendo will do with the brand