I don't think Fortnite is just a marketing platform. They wouldn't have bothered suing Apple and Google over app stores if it were merely a loss leader to remind film execs that Unreal Engine is a thing.
While I agree with you that Fortnite shouldn’t be considered a loss leader, the strategy behind challenging Apple in court is more nuanced. Epic also operates a rather large software/games store and I am sure they would love to see it grow.
