In comparison, spending on third-party titles declined by 18% to $255 million
Some key context from the article.
Basically, profit from Fortnite increased significantly, although the store itself isn't doing great.
Given that its $255 million in customer spending, not revenue or profits, and Epic reportedly takes only 12% plus reduced fees on Unreal Engine effectively lowering it further, I can't imagine its profitable. If we assume 10%, that leaves revenue of $25.5 mil, which doesn't seem like it'd be anywhere near enough to cover exclusivity deals, and giveaways, nonetheless infrastructure and other factors.