It's... unpredictably far away! We suck so bad at estimating these kinds of things, that whether it's tomorrow or 500 years from now, I'm convinced we'll be totally surprised, unprepared, and our nor even sincere effort to stear things down a good path (eg. OpenAI and such...) will be either worthless or detrimental!
We should simply pursue "organic growth" eg. grow as much people as we can care for and educate properly. Unfortunately our elites seem really hell bent of keeping the social landscape hyperconpetitive so the resources we have don't really get distributed... and as a consequence of course (rational) pople have fewer children! Also there's an intellectual war fought on "traditional values" that enabled stuff like extended famimlies to exist and make child rearing at least bearable by sharing the load of caring for the nasty little critters.