200 years ago, the majority of Americans were rural farmers, living a very different life than the average American today. They grew their own food, made their own clothes, and cooked their own meals.
This self-reliance extended ever further. Every single thing that our rural ancestors owned was either built by them, or by someone nearby. A community of a few dozen people could create every single item owned by every single member of the community. From horseshoes to plows to dresses to seeds, all of the requisite knowledge, resources, and skills were provided by the members of the community.
We live in a very different world. In looking around my modest apartment, I found it very difficult to find items that I or anyone that I know could produce. Even common items, like plastic bags, shoes, and cloth I have no idea how to make. I was washing my hands, and realized that I have no idea how the soap dispenser works.
The urbanization of the world has allowed us to increase our knowledge specialization, and decrease our knowledge density, which I will define as the proportion of the population which need to know how to make or do a certain thing. Living closer together meant that it became more efficient for a baker to make your bread than for you to make it yourself. Because bakers could spend so much of their time making bread, they soon learned more about bread-making than anyone knew before. The Internet continues to decrease our knowledge density, as knowledge can be stored and shared across the world, and across time.
This specialization of knowledge has led to a situation that is unique in human history - products which no individual understands completely. Computer software is a prime example. While there are many people who understand the basic concepts behind how a computer works, there are so many pieces layered on top of and integrated with one another, that understanding them all is impossible. Some people understand how to write a program, others understand how to compile it, others understand how the compiled program interacts with the operating system, others understand how the operating system interacts with the hardware, but I think that it would be fair to say that no one in the world has the knowledge to recreate the entire system. No one knows how a computer works.
At first, this concept is scary. While our collective knowledge has increased many times over, our individual knowledge of basic self-sufficiency has dropped dramatically. We do not know how to create even the things that we use every day. Stranded in the wilderness, we not only could not recreate the tools of today, but we couldn't even create the tools of our ancestors. We would be in much worse shape than the farmer in our introduction.
However, I think that is a price that is worth paying. By specializing our knowledge, we have been able to learn and know and do things that our ancestors couldn't even dream of. We no longer need to know how to do everything for ourselves, and that excess of time, energy, and mental capacity has allowed us to expand the borders of our societal knowledge and ability orders of magnitude faster than at any point in human history. At the same time, we have become much better at providing for our basic needs.
All of these miracles have occurred because we have embraced ignorance, and been willing not to understand.