This made me think of a comment by Lesslie Newbigin (theologian, author and missionary in India) in his Foreword to a biography of Roland Allen.
"Missionary thinking is still pervaded by Pelagianism. Mission is conceived as a task, rather than as a gift, an over-spill, and an explosion of joy." (Pelagius was a fourth century British monk who believed that salvation could be achieved entirely through human effort.)
Newbigin goes on to say...

If Allen is correct (and I think he is), the reason that the Church is not more missional is not for lack of knowledge and exhortation about mission. Rather, it is because individuals and churches do not know how to have an intimate, conversational relationship with the Holy Spirit (the "active agent" of mission). Or, as Mike Breen writes, they have "little to no idea of how to be with the King".
Get people genuinely and deeply connected to the Holy Spirit and mission will be, as Allen would say, the spontaneous and natural result.