It would make absolutely no sense that God would have some people write a book that we couldn’t believe...To write a book that is mostly allegory with out anyone being able to figure out what those things allude to...And that is the position Catholic leaders take and give to their followers...And they fall for it...
What one has to ask is what is/was their motive...The scriptures themselves show us what their motive is...
You're absolutly right. The first three centuries of Christianity were predominantly Premillennial and Christians interpreted Scripture literally. They believed God at His Word. Even Justin Martyr, the father of supersessionism, believed in Premillennialism.
All admit that premillennialism after the third century waned and lost its hold on the majority of the church. It was the time of the rising strength of the Roman Church. Both the theological and political atmosphere was against it.
I think the key to the rise of Amillennialism and the Dark Ages was the rise of the institutional church. Once the theological and political were united anything that could diminish that institutions power was disregarded.