If you look at any human activity you will find a “skill stack” involved from start to finish. For example, turning iron ore into a tool involves mining, smelting, forging, and each of those steps involves a set of skills largely unrelated to the others in the chain.
If you look at your survival skills, look at the activity of “eating” and that traces back to “cooking” and that to “gathering ingredients”, “using heat energy” and “using cookware” which all have their own skills. “Gathering ingredients” can be split into “buying”, “growing”, and “hunting” and hunting can be broken down into “harvesting” and “processing” the animal.
In short, most of us never go true “field to fork” for everything we eat. Most of us aren’t mining salt or gathering it from ocean water in order to season our meals, and most of us aren’t growing wheat to turn into flour to bake our own hot dog buns. In short, if we were to be required to master all the skills necessary to maintain our current level of civilization and comfort, we’d fail miserably.
This might be a good way for someone to do a self assessment of where they might want to invest some time and energy actually training on a new skill. Simply owning a book, and even reading a book, isn’t enough to translate “knowledge” into “useful skill.” Although having a book, and reading it, is a great first step towards learning a skill.
The saying that “you can’t do it all” is true from a practical perspective. Hence the reason why civilization is built around trade and exchange of goods and labor. If you have a “tribe” looking at the gaps in your tribe skill set might be a good way to identify a different person or tribe that you’ll want to exchange goods or labor with at some point in the future if necessary. It’s something to think about anyways.