I have no idea if this is remotely close to reality but, what if, their culture of breaking things and bad uptime is what allowed them to move fast and build a great product in the first place?
() They were founded in 2004, that's 10 years in. By that time in 2014 they had 800M+ monthly active users and $12 Billion revenue; and they had this culture internally until this point.
GitHub is an enterprise product crucial to tons of businesses.
Cultural comparisons between the two really shouldn't apply.