I would say that a very significant contingent of Protestant church men are in it for the money. We shouldn't fool ourselves into thinking that they're all sincere -- cons often come with a generous helping of scriptural glaze.
Unless you're working a seriously crazy angle like Phelps, there's generally more money to be made outside the church than within it. I think most people who have devoted their lives to a church are either sincere, or they started out sincere and started working an angle after becoming disillusioned.
