Not trying to fanboy anyone here, but while id was still in the "license the engine out for fun and profit" game (especially during the quake 2 - 3 era) they dominated. It wasn't until id tech 4 and Unreal Tournament 2004 (and the Unreal 3 engine) that they stopped being really competitive in the engine space, and Epic is as big as it is today not just because of Gears of War (was UT3 popular?) but because they own the high end licensed 3d engine space.