#1 It's "buying" not "selling".
#2 they are all politically connected so everyone within the "machine" watches out for each other. Look how most of them politically fight to keep their jobs. Most have no marketable skills other than they were able to politically help someone and get a position. Would you want to be kicked out of that group if that's all you knew for the last 20 years and try to survive in the real world? I think not. Yoru are going to do the best to protect the people who got you where you are. And you'll do if even if it's not in the best interest of the community.