And as Lubos points out even the knowledge of how-to (e.g. The Manual for Civilization) requires enough people actually doing it in order to have the resources to build more.
(How do you make a screw by yourself? You use a lathe? Who makes the parts to fix your lathe?) You need a critical mass of people who not only know how, but are actually doing stuff, in order to make better stuff.
I remember a sci-fi story from a collection ages ago in which an exec sold his soul to the devil for youth, time travel to before Henry Ford, complete specs for building a car, and enough $$ of the correct vintage to start building his factory. In the town he arrived in, the local metallurgist was a blacksmith. They knew more at a university, of course, but getting the new-fangled kinds of steel was going to be hard even in small batches. (Spoiler--he forgot to check the fine print and didn't wind up with the youth he needed either.). Even with prior knowledge, it was going to take about as long for him to build his car as it did in the real world.
Even the little pencil I linked to in an earlier post--you can construct something crude that mostly works, but the modern version has so many refinements that nobody could make one by himself. Build your own toaster?
Yes, I run into people who think they're incredibly smart because they can use the technology that a team of other people designed, and many teams of other people made, and an invisible army provides the infrastructure for.