I disagree with that conclusion: even if the chainmail were indeed very uncommon (no idea), getting it from China was so easy that he even got it when actively trying to avoid it. And since the chainmail is the revolutionary part of the idea (and the most expensive part) it might as well be the product.
He set out to get "100% made in the USA", settled for "no part made in China", and couldn't even get that. That definitely feels like a failure of the US manufacturing industry.
> That definitely feels like a failure of the US manufacturing industry.
The US manufacturing industry moved on to better paying, more stable contracts because they could.
They have no incentive to do niche things for small time YouTubers who won’t be generating repeat business.
Even the small machine shops I know now have more high paying work than they can handle. They’re just interested in doing some niche temporary work in a race to the bottom with another country that can pay workers a fraction as much and ignore all of the health and safety regulations.