This is a formidable task. Committee members are also aware that everyone should get something or there will be idle hands, unhappiness, and a general decline in morale. Sometimes this causes the really good proposals to be underfunded. Favoritism is difficult to exclude from the process. It is a very subtle thing that is hard to recognize.
People fall prey to it through omission without realizing it is happening.
And there are other agendas the committee must consider. Nowadays research must be multidisciplinary. This is also a subtle issue because who among us would not agree that multidisciplinary research is desirable. The truth is that the most likely projects to be funded are the ones that take care of all of these various elements and incorporate the new and expensive technology in which the organization has invested. And when we do get the money the project has become so large that we spend too much of our time managing the money and assuring all the elements are working smoothly while at the same time responding to countless e-mail requests for updates, etc.