This is the boldest of your bold predictions! Never say never but (imo) it will max out at around 20m. Smash has always been a more "hardcore" game than most of Nintendo's franchises so it may limit the ceiling a little.
DON'T WIN ME CHIBI BUDDY DON'T WIN ME.
ANIMAL CROSSING NEW LEAF FRIEND CODE:- 5129 1175 1029. MESSAGE ME.
ANDY MURRAY:- GRAND SLAM WINNER!
In my opinion the N64 was not just the best console of the 5th gen but, to this day the best console ever created!