I have an office job that entails a lot of interaction with people who in the construction industry, small business owners, developers, bankers, etc. I'm too androgynous for my employers to feel comfortable with letting me meet people in person (thank god) so most of it is through email or phone calls. They all vary in education and income; some have PhDs, some never finished high school, some are rich as fuck, some are struggling to get by. Most of them are local but I work with quite a few people from different parts of the country.
There's something that is common between a lot of these people, maybe even the vast majority, is that they cannot do extremely simple tasks or understand simple concepts, even when I try to explain them visually (like I'll share a spreadsheet with them and go through each individual thing I'm doing to show them what I mean). Very few of them get it. I'm not particularly smart or amazing at math or anything, but I'd like to think I can understand simple instructions. Sign this, add these numbers, make this match this. I can't imagine what it's like working in retail if the average person is this dumb.
Americans are the dumbest, most propagandized people in human history. An illiterate medieval peasant who thinks God put the king on Earth has a more accurate understanding of how the world works than the average American. Even the Americans who managed to receive an education beyond what's needed to operate a cash register almost always know nothing outside of their field. It's partially a deliberate policy and partially a result of the way hyper-Capitalist and individualist wage-slave factories we call schools have optimized for a multi-tier system of wage slaves, labor aristocracy, and managers/owners. Imparting any knowledge that isn't used to enrich the ruling class is unnecessary.