Can anyone find some reasons why management accounting practices have not evolved as they would have been expected to?
This is a difficult question to answer, because it presupposes a number of things. There are a few theoretical problems.
First, it assumes that management account has stayed stagnant. I do not know if this is true. Things have changed in the business world in many ways. Hence, this question might assume too much. Moreover, there are many companies out there. It is difficult to know what they all are doing.
Second, the question also assumes that management accounting should develop a certain way. This, too, assumes too much, in my opinion. How should thing evolve? What should it look like? It is not possible to predict how things will take shape.
Third, practices change when they have to. If things are working well, there is no need for change. I suspect that this is the case.