Can you provide a citation for this? My understanding is that humanity have spent most of its history near the carrying capacity of the environment -- world population was very stable, and the major increases in population happened due to humans figuring out new ways to increase the carrying capacity (e.g through farming), or lucking out into them (e.g. through lactose tolerance genes). At least, could you specify what excatly you mean by "modern times"?
Agree that "natural" is too often used as synonymous with "good" when our lives are far superior to what "natural" humans would experience.
The black death was a singular public health crisis precipitated by sanitation not an example of the world population periodically resetting to a manageable level.
I am not unaware of the black death I just don't think it represents an example of what poster is arguing for.
The only way to manage population is to control breeding. That is not a scaleable solution.
And that physical limit is much closer to 100 billion people, than it is to 1 billion.
Population growth is already on the downward trend, and we are expected to reach population growth neutrality by 2040.
Unless you can educate the world that the Earth has limited carrying capacity and that GDP and population growth aren't necessarily the be-all and end-all.
Your thesis other than being fictional also is an emotional appeal to the concept that what is natural is desirable which is wholly unsound both on its face and because any die out sufficient to be effective is entirely likely to not only take civization with it but also reduce our ability to take effective measures to manage our environment as our technology dies with our civilaztion.
The way forward to a managable population size is through raising everyone up to a relaively modern level and the way forward to that population living sustainably is via education.
Edit: Your philosophy that its ok for the more developed nations to wreck the environment leading to mass death presumably among those you regard as your inferiors while relax and have a latte safe behind our metaphorical walls is pure insanity.