Making all salaries public will almost certainly mean your wage costs go up. There are bound to be a range of different salaries given to people doing the same job. So all the ones at the bottom end will be turning up to the annual review demanding to be uplifted to match their peers. If they are turned down then they are likely to leave or just be less productive because they are not happy. Any need people recruited can see the public salaries and therefore negotiate a better pay deal than they might have otherwise.

It is hard to find a case where making the salaries public does not lead to higher wage costs.