Sorry you're right, but 50 million copies is not much either, when compared to Fortnite.
GTA V is the top grossing game of all time and sold 90 million copies on 3 platforms. Minecraft has sold 150 across way more platforms and has been around way longer.
This isn't about video games anymore, it's about tapping into something bigger. Even Minecraft couldn't crack into the market segments Fortnite has.