I've been in this game for a good bit now and while I've seen a bunch of go getters put in ridiculous hours and slave away and actually get promoted, I have seen faaaaaaar more just get promoted for being in the right place at the right time or, most times, being the child, spouse, in-law, or friend of someone high up in the company. In my experience your social standing or just plain luck accounts for about 90% of it. The other 10% isn't the work you do, it's the work they think you do.