[mk89]

If you do it because you are loyal to the company and you are good at what you do, you MUST be promoted. If, on the other hand, you do it because you need a promotion and all you have to do is to wait, well... I don't have the numbers, I just know that people are human, and many humans seek the best opportunities with the least effort.

[gbog]

Yes, and more often than you seem to think, "waiting" is a good choice, because it leads to better opportunities in the long term. I don't advocate to stay in the same company forever. I suggest to do exactly the opposite of the flock, i.e. leave when people are coming in, and stay when people are leaving. (That's also a way to make money on the markets, maybe the only way.)

[mk89]

I think @gbog hit the nail on the head when he mentioned waiting. This is one of the most important non-technical skills you need to learn: patience.