I had the very same thought. It is unsubstantiated. But if you consider how a game actually uses memory, it is really not suited for your run-of-the-mill GC: Most assets are allocated once per level/scene/whatever and have a pretty well-defined lifetime. What's left happily lives on the stack frame. There is may some room for reference counting of some structures (think multiplayer et. al. where the engine does not have full control of the flow). But in general, a GC can provide very little here, at quite some cost.