Basically SK is right. Epic has been pushing things a bit too much in the "overpromising" area.
It's a bit dicy to sell your tech to competitors while you still have your own high profile games to get out. Where do you decide to draw the line between game specific code and engine code? I mean how do you decide if "John" should go work on engine code to benefit the engine, or if he should go work on code for the game? Epic seems to have gone for the latter option a bit too often which leaves licensees with crappy unfinished tech.
We have shared tech in house, and we occasionally license it to other studios, but we don't whore ourselves out to everyone with spare change for this very reason. If we can't support a licensee (due to lack of resources, or being busy with our own games etc.) then they won't get a license.