Given they recently announced how much people had spent on the store, I think it's pretty much confirmed that they lost money on third party titles. IIRC the amount spent on third party titles was around 250 million. Epic gets a 12% cut, so they keep around 30 million. 10 million of that was spent getting exclusivity for Control, and Borderlands was almost certainly significantly more expensive than that. Add the money they shelled out for all those other exclusivity deals (everything from RDR2 to indie titles) and there's no way they'd come out ahead.