A dandelion has a lot of seeds because very few germinate – only a few seeds may die – fall into the water, eat animals, do not fall into the soil, etc. To survive this species and dandelions leave huge offspring, because the mother plant cannot take care of its offspring. And a person carries a new organism inside for a very long time and then takes care of it for a long time: feeds, gives water, teaches. And if he had hundreds of thousands of children, then the mother would not be able to fulfill her functions of raising and educating.
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.