I don't want to sound like a new age hippy here, but if you were to think of emotional capital as something you have to expend when you make hard decisions, I think managers have to expend a lot more emotional capital on decisions like this then they would like. And if they have to do that, it distracts them from other things.
So, to avoid expending that emotional capital, they create abstract rules and entities that they can point to and say "aww shucks, I wish we could give you more money, but This Other Thing won't let me" (whether that be HR, or a pay scale, or other things). It's usually phrased in a way to say that it's about promoting fairness or organizational principles or something like that, and it is to a point, but I think it's just as much about avoiding the hard work of managing.
The problem is that at a certain point, these abstract entities (HR and "the rules") gain more power than the managers themselves, and now the organization is incapable of doing what it needs to do because the structure it has put into place is more suited to protecting the status quo than it is to making hard but rational decisions.
So, to avoid expending that emotional capital, they create abstract rules and entities that they can point to and say "aww shucks, I wish we could give you more money, but This Other Thing won't let me" (whether that be HR, or a pay scale, or other things). It's usually phrased in a way to say that it's about promoting fairness or organizational principles or something like that, and it is to a point, but I think it's just as much about avoiding the hard work of managing.
The problem is that at a certain point, these abstract entities (HR and "the rules") gain more power than the managers themselves, and now the organization is incapable of doing what it needs to do because the structure it has put into place is more suited to protecting the status quo than it is to making hard but rational decisions.