OK, I hope my question doesn’t get misunderstood, I can see how that could happen.
Just a product of overthinking.
Idea is that we can live fairly easily even with some diseases/disorders which could be-life threatening. Many of these are hereditary.
Since modern medicine increases our survival capabilities, the “weaker” individuals can also survive and have offsprings that could potentially inherit these weaknesses, and as this continues it could perhaps leave nearly all people suffering from such conditions further into future.
Does that sound like a realistic scenario? (Assuming we don’t destroy ourselves along with the environment first…)
I’m not talking about converting new believers from outside, I’m talking about children inheriting the religion of their parents. And yes, in the places where religion has spread, only a small percentage of the population wasn’t religious, and it’s a relatively recent thing that a significant fraction of society isn’t religious.
But we still see a trend line of decreasing religiosity and a taming of extreme religious beliefs.
Children are way more likely to take the religion of their parents than otherwise, but they’re still new believers that the idea has to be able to take hold in, and if the idea just doesn’t fit then you’ll see a departure. It’s not like their religion is the only one trying to take root.
I just don’t think we see the world today that we would if religion spread with the force of population dynamics.
We see majority religions like Christianity decreasing, but minority religions are actually increasing, at least in the US.