Initially I felt the same way - but now I think Epic is taking the extremely long view. Take it this way: HOW would you possibly begin to compete with Steam, honestly, as an actual platform? Forget niche DRMs like Origin, I'm talking an entire...
I would be extremely surprised if was something provable as a policy of Valve - at the most, some manager might have intimated TOS violations which would get them delisted but there's not going to be anything listed as "If you sell your game...