I had been a game developer for last 7 years and I disagree. Most game developers do not have that much expertise to start with, because it has been a long time that low-level optimization makes or breaks your game. They tend to lean to proven techniques to the point that they have consistent aches like your aging grandparents but still keep using them because complaints alone don't break their games. The ratio of game developers capable of optimizing things at that level is roughly same to (or possibly even lower than) the ratio of comparable non-game developers.