The bishops can often articulate the feelings of many people because they do not have a political or special interest axe to grind.
On somethings they may be slow to change but in reminding government of the basic requirements of social justice and acting as a social conscience for the nation they have a very good record. I can remember Mrs Thatcher and her government getting very hot under the collar when the bishops spoke out about some of their social policies - and they had good reason, many of the social problems we now have, have their roots in the 1980s.