"Inventory" (ideally), "Overhead" or "Waste". Raw materials can at least be resold in concept, but half-assembled gear (i.e. "work-in-progress") can easily end up in a sort of parallel universe where it's not easily sold without the additional investment of time and effort (either to break it back down into components or finish it for sale) but you have to pay each month to maintain it properly until it can be finished.

It's important to remember that in traditional manufacturing at the time, each work center wasn't graded on its ability to contribute to customer sales, they were graded on things like local efficiency on a per sub-assembly basis. The "customer" wasn't the end user, the "customer" was the plant manager or the PMO or some other stand-in.

The work centers were structured around functional tasks like "heat treat" or "machining" rather than an end user product, so your "high priority" customer product had to make it through multiple independent backlogs before it could be shipped, even in theory. God forbid rework would be needed! Quality issues were the job of customer service to address, not the work center that introduced the defect (as after all, it might be years before the sub assembly finally ends up in a user's hands).