On the average of millions of privately arranged employment agreements, the employee's marginal value absolutely (slightly) exceeds their salary. You have to make a strong case that the labor market does not exhibit the properties of close to perfect competition: there are many buyers, and many sellers, of labor.

Sure, there are obviously exceptions to this calculation in both directions: how else can you explain Marissa Mayer's severance package? How else can you explain DHH's wage of $0 for maintaining Ruby on Rails?

If you can make a compelling case on this topic you can probably get published in major academic journals.