Not only epic but Apple as well. „THE APP STORE WAS NEARLY 40 PERCENT OF APPLE’S TOTAL SERVICE REVENUE IN 2019“
https://www.theverge.com/2020/8/17/...-app-store-services-business-model-epic-games
of the more than $1.8 billion earned by Fortnite in 2019, less than 12% came from iOS
12% of $1.8 billion is $276m which means a little over $120 million to Apple from Fortnite for 2019. Apple make $60 billion in a quarter, I don't think Apple is worried about losing 0.2% of it's yearly earnings. The juxtaposition is compared to Epic losing 12% of it's earnings from Fortnite or 6% of it's entire $4.2 billion revenue for the year. Epic has more to lose from this than Apple does and I suspect many who find out they can't play Fortnite will play another IAP enabled Battle Royale game and Apple might not even lose out on all of that $120 million.
If anything this is the challenge of the App Store, if Fortnite leaves then that leaves a visible vacuum in the marketplace for others to come in and try to dominate and try to get a slice of the $276m Fortnite was pulling in.