I think a lot of people, myself included, don't know the nominal value of their total compensation. If their employer pays the full costs of their health insurance plans, I don't think many people know what those costs are.

Also, as others have pointed out, certain components of total compensation, like various forms of 'equity' in the employer company, are not reasonably equivalent to cash, and no one could feasibly evaluate the cash value at any particular moment in time given all of the relevant variables needed to even estimate those cash values.