Games also have a very different set of constraints than most software. Simulating and rendering an interactive world at 60-144hz is not an easy task, and things like code cleanliness, structure and readability often lose out to performance concerns.

It's a bit of a strange thing; in my personal experience, after spending some real time with this type of constraints, it can be a bit painful to come back to "general software best practices". You become so aware of the performance implications of everything you do that all those things we do in the name of software quality can feel incredibly wasteful in terms of CPU and memory resources. One has to remind themselves that in 90% of cases that level of optimization is not warranted.