You never saw a games company from the inside did you? Major game studios are just as much entrenched in their software development processes as any other company that size. Also, there is no single 'typical' game company. You have EA or Ubisoft which put 600 people on a single project, and on the extreme other end you have the one-man-army indie developer, and everything inbetween.
In the current game dev industry, there is no longer anything "in-between". The days of the medium sized games are long gone. It is either big winner takes all or very small indie under the radar.
