As far as Smash's franchise size, it was the best selling GC game above every single title you mentioned as bigger except Mario Kart. Of course if you count handheld games then I think it goes Mario > Pokemon > Smash > others.
If you count handheldgames, Smash Melee is behind Nintendogs and Pokemon by a factor of 2, behind two different Mario and Brain Age games, and behind Animal Crossing. Smash might have been Nintendo's #2 franchise behind Pokemon 5 years ago, but things have changed.
"[Our former customers] are unable to find software which they WANT to play."
"The way to solve this problem lies in how to communicate what kind of games [they CAN play]."
Satoru Iwata, Nintendo President. Only slightly paraphrased.