Notice how I said earlier "active" accounts. I have no doubt that Minecraft has sold 7,128,000,000 copies of their game over time, but how many of those are active. If we are just talking about accounts that have been made in general, then fort nite, at one point, had 260,000,000 accounts created. In the end, even if Minecraft has more accounts than Fortnite or vice versa, it really does not matter because more people play each game than I can begin to comprehend.
