I believe the thought process was...
Smash Brothers is really successful + Sony wouldn't make a smash brothers clone unless they planned to heavily support it + I like sony mascots better then Nintendo ones so it totally should do as well if not better. (I don't but said predictor.)
The main difference I think is Nintendo mascots lend themselves to spinoffs more. The more successful Sony mascots have a certain level of grim that makes a party fighter seem kinda off... and generally aren't as popular as far as the headliners go.








