The Beginnings of Amillennialism: Defective Hermeneutic, Spiritualizing, Anti-Jewish, Anti-Physical, and Over-Realized Eschatology
I love the Reformers, Calvin, Luther, Zwingli, Carlstadt, et al. But they did not go far enough in their reforms, especially in their eschatology. However, we cannot blame them for they were preoccupied with reforming the doctrines of Scripture, Salvation, and the Church from the Roman Catholic church.
But, unfortunately, they did bring in the baggage of amillennialism from the Roman Catholic church and tweaked it only a bit.
A more important factor was the development of amillennialism before the beginning of the Roman Catholic church as we know it. Gary Vaterlaus has written a succint account here.