Honestly you're reading the data completely wrong. You cannot look at it at the country level. In Israel for example the populations that are producing the most population are highly religious and less educated than those that are producing less population.
It's more about memes. Religion is a meme driven breeding cult. This is why said religions tend to have very long term staying power. The particular problem here is these religions come at a cost of having to ignore a lot of reality to get to that point. Because they are faith based anything that presents a direct challenge to that faith must be setup as an enemy or it may risk the religion. Yes, religions can incorporate new information but it tends to be a slow process as it needs to involve slowly changing peoples mind to avoid instability.
What this looks like in the long term is large populations of highly religious that have a fundamental disconnect from the technology that's keeping them alive. A new Late Bronze Age collapse.