But when you say that only X jobs were manufacturing, while all the rest were in industries that don't "actually produce anything tangible", you seem to indicate that non-manufacturing jobs are less important, lower paying, or less real than a manufacturing job.
Just is not so.
The lawyers, accountants, bean-counters, government regulators, janitors, etc. are merely overhead for the ones who built America.
The test is simple: Who would still have a job if the other were to suddenly disappear? Example: If the people who design and build the airplanes at Boeing were suddenly to disappear, would the janitors still have a job?
No, they wouldn't.
But if you reversed it and made the janitors disappear, the engineers would still have a job.