There shouldn't be an obsession with keeping up population, with automation and AI the job market will only continue to shrink. A graceful downward trend would be better than mass unemployment.
There's two scenarios.
In the first, the technological singularity happens and everything, as we know it, changes so fundamentally that it no longer makes sense to talk about nations, cultures, or demographics. After all, what does being "Chinese" or "European" matter in a post-human world?
In the second, the technological singularity does not happen; and AI & robotics mostly enriches human civilization, enabling it to ascend to greater heights. In this scenario, demographics very much matters, and the nation that most effectively makes use of AI & robotics to augment demographic influence (via increasing fertility, colonizing space, etc.) will inherit the future.
I don't think anyone can guess which one of these scenarios will play out.
But I'm pretty sure the rational course of action is to bet on the second, since in the first scenario, what countries do literally does not matter.