It’s a vision of incredible technological progress without any growth in our ability to justly and humanely govern ourselves or move past violent conflict.
I agree with GP this is our current trajectory. I’d live in that world and hope I’d get lucky, but what a disappointment if that’s all we can manage.
The problems there were kind of organic: they just didn't need that many people, but they did have UBI, but even if you wanted to better yourself and were exceptional at your job... You could still be 50,001 in the queue of the 50,000 they needed.
Earth in the expanse desperately needed places to expand too and send people, but the solar system just wasn't that habitable.
I agree with your analysis of the cause of Earth's troubles, though I'm not sure that adds up to not much being wrong with it. The Earth in the Expanse never figured out how to deal with "excess humans" and the result was planet-Baltimore, that seems pretty wrong to me. And I don't think it's too soon for us to be taking a hard look at how this is likely to work out on the real Earth.
The main series takes place over about 30 years during which several billion people die system-wide as a result of various wars and terrorist attacks, and uncountably many die in the immediate aftermath of the finale. I love it but it's not really a feel-good story!