I don’t think we’re facing an existential crisis in relation to the amount of humans being born any time soon. It’s rather quite the opposite, the population continues to grow, some people are worries about over population, because the average life span of humans has almost doubled. There are serious issues going on in the world, like the many humans destroying mother Gaia and I think that’s more of a valid concern, extinction due to natural disaster. But I’d have to do more research on the topic to understand where your points come from.