Everyone has got valid points here, but i think it comes down to the point that Bernie made earlier:

"The intensive effort involved in Supplier Performance Measurement is a major hurdle for some procurement professionals. As a result they sometimes give up on the leading practice purely because they do not have the resourses / time to do this.

With the correct "tools" for the job it can be done efficiently and effectively and when this is the case organisations realise alot of value.

Even when you pass things over to the supplier because of resource contraints dont bet on the supplier having a whole lot of resources in place to do the job either. Remeber they are also in business and dont just have extra resources wondering around the place. People always fail to consider that if you pass on your practices to the supplier, you need to evaluate the cost implication of such an approach. Because i can guarantee you that the supplier will pass those costs on to the customer organisation.