Why have many Activity-Based Costing (ABC) systems failed?

Why have many Activity-Based Costing (ABC) systems failed?For your reference....What Is Activity-Based Costing:Simply put, activity-based costing is a process where costs are assigned due to the cause and effect relationship between costs and the activities that drive costs. Traditional costing systems have a tendency to assign indirect costs based on something easy to identify (such as direct labor hours). This method to assigning costs can be very inaccurate, as there is not necessarily a relationship between the costs that are being assigned, and the activity they are being assigned to. This can make evaluating costs tricky and inaccurate.Read more at Suite101: Activity-Based Costing (ABC): Types of Accounting Costing Systems http://www.suite101.com/content/activitybased-costing-abc-a52148#ixzz0zRYKWQYg