This may bode well for id software, oddly enough. At E3 they showed id Tech 5 running on PC, Mac, 360, and PS3 all at speed, all using the same assets. In fact the artists that made the assets had no idea they were going to be used on the PS3. Looks to be a multi-platform dream engine.
So if this case goes south for Epic and devs get fed up with the engine, id will be there to show off their stuff.