One problem is that one wants an objective way to judge someone’s productivity. You cannot truly judge the quality of a paper unless you are an expert in that same field. Your institution may not have such an expert. Besides, in science you really don’t want to rely on personal judgment, if possible. Maybe there’s also marketing efforts going on that encourage doing things in away that allows extracting monopoly rents but I don’t have evidence.
IMHO the overarching problem is that the whole of academic publishing has not arrived in the internet age. You have all the usual problems with reforming social systems and, on top of that, there’s a lot of money at stake for some people.