You go through the trouble of collecting all 8 badges and defeating the Elite Four—and in some cases, sometimes you even try to catch them all. But what for? Pokémon games sometimes treat you rather poorly after doing all that work, when you think about it.
Sure, new areas and quests open up, and in the case of X & Y, you even get a parade (which your own mom doesn't attend, for whatever reason). But still! You don't really get to revel in the fact that now you're the CHAMPION or anything. The games typically don't really acknowledge it, you're just, like, some dude or something. Which is bullshit.
Dorkly postulates that there's a reason for all of this—though their theory meshes the best with the original Pokémon games, Red and Blue:
You can read more Dorkly comics here.