Fortnite's annual revenue was $6 billion last year. Assume operating an app store costs $10 million/year/platform they only need to sell $30 million of Fortnite

Fortnite's annual revenue was $6 billion last year. Assume operating an app store costs $10 million/year/platform they only need to sell $30 million of Fortnite to break even relative to the world where they're giving Apple 30% of their profits. They're not "competing" with Steam they're doing in-house publishing, which likely saves tens if not hundreds of millions of dollars which would otherwise be free profit for Apple.