Just because a "system" has worked one way for an extended period of time is not a guarantee that it must continue thusly.

I worked with the CA Catholic Conference many years ago and it depended on WHO was in leadership, WHAT was accomplished....I was trained as a lobbyist by their social welfare lobbyist and donated a salary for two legislative sessions to expand that lobbying. And we promoted a lot of local (diocesan) political support for that legislation.... 

 In fact the bishops lobbyist very frequently asked at the local diocesan level for specific political response. This is a common practice...used by many.

On the other hand if you have an obstructionist leadership that is not supportive of active political intervention..but rather prefers a very slow and indifferent response at the national level.... than the ad hoc committee structure is your baby....

In many ways it's the difference at the national-local level of political response between NETWORK and the USCCB!