In fact, second lieutenants were primary-school teachers. Sure, teachers with guns, but a platoon commander was, nonetheless, the guy who sorted out the working day for 30 men under his command, taught their lessons, helped them with their homework, sorted out their petty squabbles and put plasters on their knees when they fell over in the playground.
The farm work they hated was the only work they knew. Often, even the basic skills of plumbing or electricity or mechanical work were mysteries to them – as were the job discipline and the subtleties that children raised in the industrial world learn without thinking about them; starting work on time, working set hours, taking orders from strangers instead of their father, playing office politics.
If you want to be relevant only in your household, then you only need to know the things that are important in your house, and if you want to be relevant in your neighborhood, you need to know what's important in your neighborhood. The same thing applies to your city, state, and country. And if you want to be relevant to the entire world, program that computer known as your brain with all kinds of information from everywhere in order to prepare yourself.