>>42426282I'll give you 3 clear reasons
1)She's the original waifumon
You can talk about Jinx and Nidoqueen having big tits despite the former being a hideous living wig and the latter being a dinosaur looking rabbit but Gardevoir was the most humanoid out of all the femenine pokemons
2) (more like 1.5) she debutted in the third generation of pokemon while Tsareena came out last generation, Gardevoir has a decade and a half worth of legacy and recent waifumons that attempt to be the next gardevoir just won't come to the same level as Garde (some were close though, Lopunny and Braixen are second to Garde) and not only did gardevoir came out in gen 3, she was also amazing in-game and if we talk competitive mons, she was decent because it had great coverage because back then the elemental punches and could run some other sets and her stats were pretty serviceable as a wallbreaker which was enough to make her UUBL. Although gens 4 and 5 weren't kind because she was outclassed all around and all it took was a fairy typing and a mega to make garde great
3)And possibly the absolute most important reason why Gardevoir has remained on the top of the pokewaifu charts: Mystery Dungeon, Gardevoir was a key character in the game and we all know how her backstory went and not only that but there's also the postgame chapter where you get to give a bittersweet closure to her character.
In simple terms, Gardevoir not only is the OG but has enough to prove that she's THE waifumon with how relevant she is in the franchise, and again, pokemon mystery dungeon rescue team will give you an idea that Gardevoir takes her role as a waifumon to the point she'll die for you so fuck off with not just the cuck shit but also with the "but pokemon can't consent because they're like animals :(", Gardevoir will be glad to be there for you, in the good, the bad and the ugly times.