What is the point in the fact that some animals have many stages in the life cycle, while others have few?

Animals with several stages of development in the life cycle (insects, amphibians, worms) ensure the greatest survival of individuals in nature. In their life cycle, there are stages in which the larvae differ from the adults in the type of feeding and movement. This avoids competition with adults. The larvae of many animals live in the soil, which provides additional protection. Also, in animals with several stages, the offspring make up a huge number of which a lot die. The number of juveniles ensures the survival of many animals.