Understanding childhood development is a modern view that comes from psychology in a modern world. The theories come from the observation of many children. There are many well known theorists who tried to explain what they saw in terms of children’s development. However, these views are very influenced by their cultural context and era. They have in tern influenced cultural understandings of children.
You can find a summary of the main theorists here.
In terms of the tricky territory of parenting advice the two best books I read when raising my own children were Raising our children raising ourselves which focuses on helping parents grow alongside their children and the other was a history of child care manuals and parenting advice books which made me go back to my own intuitions about my children. So I want to say that my explorations on the podcast are to act only as stimuli to re-thinking assumptions, and deepen our observations.
If we could bring our toddlers to visit indigenous toddlers or time travel and see some of the earliest Homo Sapien toddlers, and bring some toddlers from our time and left them to hang out, they would be content in that environment. The toddlers would develop and learn in much the same ways. We adults might not be as content as we are have adapted to, and become comfortable in, a very different environment.
I have always gone back to what I know or can imagine about our indigenous or ancient roots to try to understand the main needs for children at different stages, and choices in the ways we meet these needs. I never read the book the Continuum Concept but I believe this approach has much in common with my thinking.
I think there are insights from this exploration of how we view children and their play for adults seeking to find balance in their own well-being or mental health.