Earlier quoted context omitted.
The nature of evolution dictates that, even without a collapse in our ability to harvest energy and other resources from the environment, life is destined to get worse for the median human being. There are only so many resources to be consumed, but life reproduces exponentially.
> life reproduces exponentially Life in general does. Humans, however, seem to be abandoning this trend.
It's temporary. Most humans are poorly adapted to modern life. But not all. The transition back to higher fertility is already underway, it's just hard to notice because the percentage of people who are well adapted to modernity is really small. But there are people who have 4+ kids, despite living in the developed world. Those are the humans of the future.