>>57797667He was in the right place at the right time culturally speaking.
>Mid to late 2000s>Videogames in general were going through an "edgy and "I'm an ADULT now, mom!" phase>Most Pokemon fans that grew up with gens 1-3 are teenagers now and wanted to express their more "mature" side once DPPt came out>Lucario and Riolu were literally the most shonen looking motherfuckers in the series at that point with ALL the stereotypes kids who love Naruto, Dragonball, and One Piece love (Entire personality centered around growing stronger and fighting to protect the ones they love, cool aura powers, martial arts mixed with energy beam/ball attacks, a cool bone sword as it's special move only they could learn)Add all of the above with the sexual subgroup of 90s Furries and Pokemon's cultural dominance and you can easily see why Lucario and all
his copycats ended up being so loved in more ways than one...
Also he was MASSIVELY shilled literally ever since his debut. Got put into Super Small Bros. Brawl over fucking Mewtwo. Got his own special cool looking trainer in the anime. Even got a Mega Evolution just to cement how "cool" he can be.