comparing sales of specific video games to specific albums seems like a weird comparison. for every one purchase of an album, there will be many people who hear it without purchasing it (on the radio, in restaurants, while shopping, etc.). the only legal way to experience a videogame without purchasing a copy is to play at a friend's house. games like fortnite might rival the most famous pop stars today in cultural significance, but I don't think you could say the same for GTA vs Britney Spears in the mid 00's.