But population is critical. It is the demand side of supply and demand. People need food, shelter, etc. and more people = more demand = more GDP. Less people = less demand = less GDP. Yet our current economic model can't allow declining population and declining GDP, because it is debt based. Our money is debt based money. How does a debt based money work in a shrinking economy? It just makes the debt more unpayable.
And I believe the most important thing is that once the collapse really gets started, it will be self fueling, because the population decline will cause a never ending depression, which will cause adults to not want to have children they can't afford and can't guarantee they will have a life even equal to their own, which lowers the population, and causes greater economic contraction.
I’m still not seeing how you can say the author “seems to be a Malthus adherent”. That may be true but I don’t see how you can conclude that from this article. (I haven’t read any other articles from her so I can’t say is she is or isn’t)