Dear Teacher, with your examples (read, write, maths, science), it is easy to learn these ‘subjects’ organically on your own or in a group. There is not one way to do those things. and there are many resources available to aid understanding. Also, all these ‘subjects’ can be learned during the process of play. The children would not learn them as ‘subjects’ because that is an artificial construct in order to fit in with the traditional school model.
Of course, we can dance in or own way, however, if someone wants to learn a specific skill that needs instruction, like ballet or yoga, it’s easier to have someone instruct us.

A common question! I once thought reading HAD to be taught. Turns out it actually doesn’t and unschooled kids teach themselves to read easily 🙂 This explains it well: https://www.psychologytoday.com/blog/freedom-learn/201002/children-teach-themselves-read