The original Unreal engine has been developed for a commercial game same as Torque for Tribes
I remember the flame war 3dgs vs Torque
I was on 3dgs side
The point was that 3dgs was a multipurpose engine while Torque was much better than 3dgs but for some types of games only , a nightmare for anything else

Nowadays Torque is dead while 3dgs is still (more or less) alive

I wonder whether the same story is going to be repeated , Unity vs Unreal 4