>>37219000Greninja's a different case.
People quickly got over it abandoning the Bubbles in favor of a long ass tongue and it suddenly skyrocketed in popularity with EVERYONE.
Casuals liked it because it was edgy, kids liked it because it was edgy, competitivefags liked it because it was the very first starter to actually be "overpowered" without needing a Mega, furries liked it because it could easily be molded into whatever the hell they wanted, the list goes on.
Greninja getting in Smash made it even more popular, but the only thing it did from there was elevate it into being the second most popular starter of all time.
Incineroar only had a small following prior to Smash.