I've read the Microsoft Windows OS is so large that you couldn't view the whole thing in a lifetime if you read a page a second. That's just one piece of software, and involving various computer related fields.

It's been a long, long time since we didn't have to already specialize to a degree. Think of whitesmiths and blacksmiths. Even old fields required specializing. It's no different than today. You don't need to know every single detail to contribute to the whole.