The point is not membership. The church does not have clients, members, or consumers of goods and services. The point is discipleship. The church exists to form and sustain individuals and a people who are followers of Jesus Christ, who are his disciples. Rather than buying into a consumer model of the church, where the customer is king and the church simply meets customers' needs, the church does more; the church redefines our true needs. The church transforms people according to the life and pattern revealed by God in Jesus Christ. It unites them with others who are committed to this way of life.
I would agree that this is a huge challenge. It is part of our church culture that has pervaded for so long that even among people who "know better" it is so easy to slip back into the membership mentality. Good stuff.