Well in reality I think alot has to do with who you know, who has your back, and how likeable you are. Thats why they use the term "connected", how well connected you are to the right people will determine how far you get [ in most cases ]. Look at the guys at the top, most captains are sons or nephews of captains.

Then on the other end we all see guys who did hit after hit, job after job, time in the can, etc for decades and never even got made or just barely got made at the end of their careers. Best career move you could make, if you had no connections in that life, would be to marry the fat daughter of a powerful captain.