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.