Think US Evangelicals Are Dying Out? Well, Define Evangelicalism source
Religious evangelicals may look at these numbers and think, “This is not what the term evangelical means.” The assumption is that the term describes those who place high value on the teachings of the Bible and strive to evangelize other people into their faith. However, that understanding of the term seems to be fading, replaced with a more amorphous concept that melds together religious doctrine and an affinity for conservative politics that experts are only beginning to understand now.
The above is a bug, not a feature. One can argue that the assimilation of Christianity into the Roman Empire in 313 huge negative consequences on Christianity, and it probably was not good for empire either.
Secular power always, always, seeks to consolidate power with religion.