Some groups and some individuals have a hard time disagreeing with authority, especially doctors. Membership in any one CAB can be boring, unsatisfying, and frustrating, like any real job. But the demands of many CABs tax the ability of those interested and willing to participate. The job of the CAB is not recruitment or self-improvement, or making trips to Washington. It is advising in an often-thankless effort to improve and speed up research.
Many CABs are too small and have too much to cover and do.
New members are often left to shift for themselves in a world of acronyms and details. Impacted cities have CAB gridlock, and there are never enough smart, determined activists to man or woman them. Many working members don't have a lot of time to devote to CAB business in the networks, which can occur during business hours or at distant meetings. But imperfect as the system is, it accomplishes great, often unrecognized improvements. Often at the national level, there's a conflict between representing a particular constituency and working together with others, in doing the hard work of participating in the scientific enterprise by understanding what the scientific needs are, and seeing what's best for our communities at large.