In a completely hypothetical situation, where a human came into being fully formed with complete knowledge of how to do a thing and all the resources to do it s

In a completely hypothetical situation, where a human came into being fully formed with complete knowledge of how to do a thing and all the resources to do it spawned out of the void around them, then yes, they could produce something purely out of their own labor. In any real situation, the very existence of that human at any age past infancy is the product of society. Even back to the first proto-hominids. So is the knowledge to be able to produce the thing. In any modern situation, the resources and tools that human has at their disposal are also products of society (yes, even "natural" products like wood—at least in America, there are nearly no old-growth forests left, and literally every natural resource has to either be cultivated or protected in some way, or extracted with nontrivial tools). Again: you are only able to come to your libertarian-fantasy conclusion by narrowing your focus to the single act, rather than being willing to acknowledge all the supports that make it possible.