It's actually the other way around.
If the world were perfect, it would be. However, in my experience, it doesn't work that way. I saw numerous people who were good at the social game and spotlighting (performing well when someone is looking) get ahead. I've even seen people who simply looked the part (tall and athletic) be promoted faster than those who was better than them in literally every test - practical and paper.
I was even on a board for a meritorious promotion and I was the sole person against one of the selections who got along well with the leadership. I didn't think he was mature enough to handle the responsibilities but everyone said he was a great guy, and would be fine. Short version: They promoted him and two months later he was busted back down for assaulting an officer while out drinking.
While you need a certain level of knowledge and ability, once you have that how well you do is often based on how tall, athletic and attractive you are. I don't have access to the entire paper, but you can look at an interesting abstract here.