Ultimately if secular society was better then a secular society should have "won". Secular societies in the modern world have either failed or are on their way to failure, again I point to the unsustainably low birth rates for that one. Secular people simply tend self-select themselves out of the gene pool when having kids is no longer a necessity and birth control makes it easy to avoid having them, while devoutly religious people tend to (as the Abrahamic God commanded) "be fruitful and multiply". Again, just look at the Mormon fertility rate for an obvious example of this.

The Christian civilization that rose out of the Roman empire is what won. Partly due to geography, but partly due to the cultural values that were largely derived from Christianity made it possible. There have always been times when discoveries were a tough pill to swallow for the religious types, but eventually most swallow it. You'd have a hard time finding a flat-earther today, and in a few more generations you'll have just as hard a time finding a Christian who doesn't believe in evolution.