You're making a philosophical and economic argument that is worth separating into a few parts. First, there is a well-documented observation in demography often called the "demographic transition": as societies become more prosperous, healthier, more educated, and more secure, fertility rates often decline. Families tend to choose fewer children when child survival is high, education is widespread, women have greater opportunities, and old-age security is less dependent on having many offspring. From that perspective, your argument is: If prosperity naturally tends to reduce birth rates, then coercive population-control measures are unnecessary. Prosperity itself becomes the stabilizing mechanism. You then take the argument further and suggest that eugenics is not really about population stabilization at all. In your view, if prosperity can achieve lower fertility voluntarily, then eugenic policies would only be pursued by those seeking selective exclusion or elimination of certain groups rather than demographic stability. You also connect this to economics, arguing that systematically removing vulnerable people could reduce overall participation in society and consumption, harming aggregate demand rather than strengthening prosperity. That is an economic claim that some economists might partly agree with, in the sense that large populations of consumers, workers, caregivers, innovators, and community members all contribute to economic activity. People with disabilities are not merely recipients of support; they also contribute labor, creativity, demand, culture, and social capital.
