The short answer is because it has been far more like the “M’s” on the left than those on the right.
North American Christianity Missional
Museum Mission Outpost
Memorial Mental Health Center
Mausoleum MASH Unit
Mall Meeting Hall
Museum: Church is about the past, the ”good old days,” when things were supposedly better and God's presence and power more evident to all. The dominant dynamic is nostalgia; the primary leadership posture is Curator. This person is responsible for preserving the relics and maintaining the memory which gives the people its identity.
Mission Outpost: Church is about the present in light of the future of God's coming Kingdom. It is forward/future oriented, honoring the past but moving on into the new and different future where God is already at work blazing trails and creating opportunities for his people. The dominant dynamic is hope. The primary leadership posture is collegial, gift-based, and focused on poetry – envisioning and discerning God's future, prophecy – declaring God's present will for a people on the move, and apostolicity – leading into the future without a set of maps.
Memorial: Church is about remembering Jesus, the Jesus who would set all things right . . . if he were only here! The church tries hard to do what Jesus would do and clings firmly to orthodox teaching about Jesus. The dominant dynamic here is the past. This is not the nostalgia of the Church as “Museum,” however; it is more of a confidence that if the church can get the earthly Jesus right historically, it will be able to forge ahead with confidence and strength. This is the churchly version of modernity's confidence in reason and history. The primary leadership posture is Teacher/Scholar.
Mental Health Center: Church is indeed about the business of cognitive adjustment. But trusting in the presence of the living Jesus through his Spirit the church strives to discover what he is doing now in the world in order to join him in that work. There is a remembering of Jesus involved but it is in the Hebraic sense of re-encountering Jesus in his risen and living reality and thus being re-membered into his body. As one black preacher told Will Willimon, black worship takes so long because after a week in a world that routinely dismisses, demeans, and dehumanizes black people, it takes three hours for him to get their minds and heart reoriented and focused on Jesus and centered in the gospel affirmation of who they are in Christ. The dominant dynamic here is the present and the need to encounter the risen and living One. The primary Leadership posture is mentor.
Mausoleum: Church is the burial place of Jesus. He is dead and gone, a nobly tragic figure, a good example, perhaps the best person who ever lived, but that is all. Jesus is revered here, admired and acclaimed, but he is finally a human being. And like all human beings, death has claimed him. The church remembers Jesus as mourners. Low grade grief, lack of expectation, and even a silent despair like a fever runs through the life of these churches as their dominant dynamic. The primary leadership profile is that of therapist-caretaker.
M.A.S.H. Unit: the issue of health looms large here too. However, it is our health as followers of Jesus who bring to him our wounds, hurts, and struggles acquired in the journey. Jesus is the living One, the Great Physician, who will not the power of death and evil to reign over them. In the church he meets us with healing as we share with him all that ails us. Jesus heals us enough so that we may rejoin the fray and pick up with our journey of discipleship. Full healing and rest still await us but Jesus gives us the healing we need to continue on with the work. The dominant dynamic here is well-being. The primary leadership posture is Spiritual Guide or Director.
Mall: Church is about meeting the “felt needs” of the congregation. Mega-churches have the resources to fully service their members and thus they illustrate this “Church as Mall” model well. They often identify themselves as “24/7” institutions which are “there” all day, every day, in every way for their people. The dominant dynamic is, to put it crassly, “Customer Service.” This becomes not only the programmatic baseline but the basis for its appeal to the community as well. “Join us and We Will Take Care of You and Your Family.” The primary Leadership posture is the C.E.O.
Meeting Hall: The Church here serves as a center for the community's missional deliberation. The Greek word for “church” means just that, a “town hall assembly” to take care of community business. The dominant dynamic is discernment – looking outward to discover where God is leading his people into ministry. The primary Leadership posture is facilitator.
Mystification: The end result of the models and methods embraced by most North American Christianity ends up by mystifying the church. That is, over its theology, worship, and work lies a pall of unreality and confusion. As Walker Percy puts it in The Thanatos Syndrome, the words of the church “no longer signify.” This mystification is the crisis of the North American church as we move on into the 21st century.
Mysticism: A missional church lives from its relation to its Lord. At the heart of this way of being church is a practical mysticism, that is, the ability to discern God's presence in daily life and come to experience life as prayer, that is, an ongoing conversation and companionship with God throughout their lives.
McDonalds: Church in North American has bought into the values of “McDonaldization” - efficiency, calculability, predictability, and control. These values, central to North American culture, drive the sense of mystification that now pervades the church and allow the “mystery” at the heart of the church, the presence of the triune God, to atrophy.
Monastery: Missional church, by focusing on the relation to God in the midst of life, in other words, the Holy Spirit, takes the form of a monastery in the midst of the world. A “monastic” missional church seeks to reintegrate the experience of the living God at the heart of a people living and loving the world as God's missional people.