Who wants to be a millwright? Or a production engineer? To build a factory, you need both. Once you've built the factory, you don't need most of them them any more. It's a job with high layoff potential. Top pay is maybe $125K.
You need people who've built your kind of factory before. Here, they need people who've built mechanized hot forging shops. Since few of those are built in the US each year, there's no pool of such people.
Stanley, the company, had forgotten how to build a plant like that. They relied on the equipment manufacturer, and perhaps some consultants. That didn't work out.
It takes a long time to get a good factory going from a cold start. It took Airbus 21 years before they made a good airplane. It took Tesla 15 years from start to significant production volume.