"In days to come the mountain of the Lord's house shall be established as the highest of the mountains, and shall be raised above the hills; all the nations shall stream to it.
"Many people shall come and say, 'Come, let us go up to the mountain of the Lord, to the house of the God of Jacob, that he may teach us his ways, and that we may walk in his paths.'" Isaiah 2:2-3a (NRSV)
The main reason why this has not happened in the past is because the Churches were not teaching the ways of God.
The Christian Churches preached a version of Christology which did not reflect the pacifist, forgiving, loving nature of God.
How could the nations learn the ways of God if His own Churches did not teach them?
As I have said elsewhere, this is because the conservative establishment usurped the absolute power of Christ and modified Jesus' message of love and forgiveness to suit their own power and position.
We are only now beginning to see the true nature of Jesus' message as Progressive Christianity deconstructs the scriptures to reveal the true ways of God: unconditional love, forgiveness, benevolence, and equality.
[Scripture quotations (marked NRSV) are taken from the New Revised Standard Version Bible, copyright 1989 by the Division of Christian Education of the National Council of the Churches of Christ in the U.S.A., and are used by permission. All rights reserved.]