The major factor at work is simply a lack of personal responsibility towards the end product in a large company. In a startup there's noone to blame but you, a

The major factor at work is simply a lack of personal responsibility towards the end product in a large company. In a startup there's noone to blame but you, and thus no need for politics. As anyone who has worked in middle management or above in a large company can tell you half of the job is making sure you can always find someone else to blame, while taking credit for the successes of others.