Epic is conveying that the 30% cut on App Store was raising the prices. But Xbox and PlayStation has the same cut, yet Epic has lower pricing on these platforms.
Are you sure Epic hasn't negotiated some sort of deal with Xbox and playstation to lower the cut to a more reasonable rate given their volume of transactions.
To clarify, I work in the gaming industry and I've heard rumors of large publishers negotiating better terms when they get to a certain magical number of transactions/gross rev. I'm not sure I've read any reporting on it. The sources I heard this from would have been in a position to know but, I can't really point to any hard data. I wouldn't be at all surprised if it were true. I've heard it can be as low as 10-15% but again I don't have any evidence on that.
I don't think it's realistic to assume that 30% of all Fortnite revenues on xbox/playstation is still going to the platform holders. Valve already offers a 20% cut to large-volume titles on Steam, so it's plausible that Epic would have a custom deal with the console vendors.