Many internal game engines go through similar levels of churn + updates, they just usually don't see the light of day. Gamedev is a somewhat unique space in th

Many internal game engines go through similar levels of churn + updates, they just usually don't see the light of day. Gamedev is a somewhat unique space in that about 6 months from ship you fork from upstream and almost never merge again. Heck most licensees I know hacked UE3 to hell-and-back(which we did too) to add the features that we need to actually ship.