The US is terrible with labor laws, by design. It’s absurd, especially immediately after civic when all these"essential workers" were called “heroes” but weren’t compensated as such. And when nobody was applying for jobs that were paid trash and got shit on by management and customers should the only reaction was “nobody wants to work anymore”.
No, people wanna work. They just don’t want to be paid minimum wage for skilled positions and spend half the day being berated
Also the time needed to perfect that skill wouldn’t have been available that far back. If you’re needing to spend the bulk of your time hunting/gathering food and other forms of basic survival I don’t think you’d have the hours every evening to work on your shading techniques.