But the individuals in populations that are in balance with their environment are, on the whole, pretty healthy looking. The potential for exponential growth is held in check by predation (of herbivores) and by competition for resources, territory or mates - not only achieving a stable population but improving the survival characteristics of the species in the environment.
Humans have pushed the natural population controls - we have no serious predators, we have made technological advances - agriculture, industrialisation and communications technology - and we grow - exponentially.
Poverty around the world is taking on Malthusian grimness - individuals are suffering but the population is still increasing. The idea that technology can reduce our per capita need for resources in order to have a good life has its limits. This is a possibility for stable populations - not growing ones.
And miserable poverty is contrasted with extreme wealth. How can this be good for the species? Does wealth need poverty in order to exist? Is this a zero sum game that relies on a "feedstock" of misery?
Our capacity to control our population need not be horrible - we achieve more benefit from compassion and cooperation than we do from war and murder. Contraception is better for parents and children than infanticide, starvation, contagion or abortion. As has been pointed out - people will be OK with small families if they have the luxury of being able to love the children that they have - because they know they will not only survive but have the chance to flourish.
And what constitutes "improvement" in the human species? I would suggest
Our capacity to live together in harmony and develop the talents of every member of the community - respect for diversity, creative rather than destructive outlets for aggression
Our capacity to respect, learn from and live with and within our environment
Improved mental and physical health of every member of the community
A cultural life that enhances the capacity for aesthetic pleasure, and spiritual growthNow I'll go and think about the carbon footprint of my sculpture practice.