Main point of the article (quoted):

> In 2017, Tim Cook came as close as he ever has to publicly addressing the issue. "In the US," he said, "you could have a meeting of tooling engineers, and I'm not sure you could fill the room. In China, you could fill multiple football fields."

One possible reason for this is that US education is generally broad compared to other countries. No one in America majors in "tool engineering" but a mechanical engineer could certainly be trained for the job. In other countries such as Germany and China you're more likely to follow a more narrow path (for better or worse).