From the company's perspective, it's really hard to effect real fairness in pay. For example, how do you weigh someone who has 30yrs of 2-4% annual raises with

From the company's perspective, it's really hard to effect real fairness in pay. For example, how do you weigh someone who has 30yrs of 2-4% annual raises with a new hire who may be a hotshot but is never going to be brought on with an equivalent salary? Or, how do you handle geographically inequality? Or, what about collective bargaining agreements and mandatory increases that only affect a subset of the organization? If everyone's pay was published it would lead to lots of unpleasant questions, questions that don't have satisfactory answers in many cases.