I was going through the list of game engines on Wikipedia (http://en.wikipedia.org/wiki/List_of_game_engines) and was amazed to see that the primary programming language for most of them was C/C++.
Another factor is predictability. When you write a line of code in a low-level language like C, you have a reasonably accurate approximation of what the machine is actually going to do for you at that point. Moreover, things like memory management are manual and explicit, and you have a reasonably good idea of when they happen and how long they take. In comparison, a lot of higher languages have a significant and not necessarily predictable overhead in the runtime and/or VM.