I think that this is a much older sentiment than modern corporations. For one thing the aversion to discussing wealth is more potent in contexts where the infor

I think that this is a much older sentiment than modern corporations. For one thing the aversion to discussing wealth is more potent in contexts where the information is less related to market forces - people are more open to information about salaries when it is related to their line of work. Saying how much money you make in public (even among friends) is seen as a jerk thing to do. Instead people will say things like 'the starting salary in my field is...', or 'a senior level employee doing this makes around...' - a actual number for them personally is seldom offered (nor should it be outside of very intimate contexts (family). From an informal observation this prohibition is common across Protestant societies, though I think it also shows up around the globe. Talking about money publicly is seen as vulgar and viewing people in terms of money is seen as demeaning to their fundamental worth. You can find religious antecedents to such sentiments from thousands of years ago, so it is unlikely that these were promulgated by corporate interests.