What does the balance of barganing power between the employer and employee means?

For the employee, lets say that they are really good at what they do and bring in lots of money for a business, he can command a higher salary. For the employer, if the business is exclusive and tough to get a job at, they will see better qualified people apply for the positions and be willing to take less pay, for a while, just to get a foot in the door. Every business has its highs and lows and what alot of business owners forget is its the little people that make them big.