I'd say the main reason is that video games companies are usually run by a bunch of amateurs who are good at a few particular things (coding, design, creativity, and maybe even "hyping" things) but have shortcomings when it comes to engineering and delivering consistent, solid quality. Many companies dont have regular processes, and rely on employees forsaking weekends in order to deliver things on time.
I know it's usually not popular here to talk about the necessity of Project Managers, but the Video Games Industry is a pretty good example of an situation where more (i.e. better) management could help make things better compared to the current mess.