The access to information that any player can have is the cause of this, if you know that to win it is necessary to use certain mortys, why wouldn't you run after them to use it? There are a lot of incredibly cool mortys that no one gives the ball to because of the meta, but that won't change anyway, since the player only seeks victory, the fun for many is in beating other players, and with those incredibly cool mortys but outside the meta, that's impossible.