Of course, very few would dare to do that because they know that the data will be hiding all sorts of embarrassing and possibly resignation-causing truths. Which is kind of shitty if you think about it, especially when taken with the notion that "companies are people"... sociopathic, lying, cheating people...
For one thing, fairness is subjective. For many, "equal pay for equal work" is fair, but many others believe that seniority, or a better CV, or many others factors should be rewarded differently.
Secondly, there are issues of perception. A worker might think (s)he should be paid more because (s)he always leaves later than his/her colleague, without taking into account that the colleague prefers to take shorter lunches or fewer breaks and leave earlier. You can explain it to them, but why would they believe you?
It'd be different if a company published the salaries from the start, but switching after growing to a huge size can be very disruptive, and I don't blame managers for avoiding opening that can of worms.
(Again, I don't believe the salaries at Google are perfectly fair, I'm talking about an hypothetical company)