The reason for the rapid population growth in the XIX century. there was a decrease in mortality due to the achievements of science, economic growth, the success of sanitation and hygiene. Due to improved nutrition, people have become physically stronger. Medical services (including vaccinations) rose to a new level and the end of the XIX century. became systematic. The introduction of plumbing and sanitation, personal hygiene, and even just boiling water and milk reduced the risk of infectious diseases. Monstrous epidemics of a European scale are gone, the victims of which were hundreds of thousands of people.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.