The average gamer cares for performance, but the Pokemon players are not the average game, they are Pokemon fans
It's a game that sold more than 15 million copies in EVERY entry regardless of the platform it was released. It's clear a game that have a subculture of fans that will buy it no matter in whatever poor state the game is. As long the gamr can run without crashing all time Pokemon fans are going to enjoy it
They are just too passionate about the BRAND. Focus on the keyword here: The brand. Does it have Pikachu in the cover? They will like it