Just-in-Time supply chain management theory presumes that inputs are fungible and outputs can be on-demand.
Capital intensive industries are risky because past and present investment is not a guarantee of a future profit.
If the DoD wants a stable domestic supply chain, they'll need to implement procurement practices to normalize national security vendor business cycles. The Agriculture Department has programs to normalize the corn-hog cycle to provide price stability for food production.
Publicly traded stock companies are discourage by Wall Street from keeping too much cash on-hand. If a company has "too much" cash, activist shareholders will push to have that cash returned to investors, preferrably in the form of tax-efficient stock buy-backs.
My father worked in the Defense sector during the 1960's - late 1980's. As an employee of a defense contractor, he was subject to employment / unemployment cycles as Defense programs were funded or cancelled. This was not stable enough to provide for a young family. After a layoff / furlough in the early 1980's, he left the defense contractor to work as a consultant at smaller defense subcontractors, communications subcontractors, and medical subcontractors.
Skilled positions require significant upfront time and upfront money to be expended to acquire and develop the requisite skills. If a career field requires taking significant upfront risk, by an employer or by a worker, there needs to be a return on investment that makes that risk worth taking.
If a skill field has a high barrier to entry and a low or negative return on investment, employees and employers will risk their capital (time, money, opportunity) to pursue more profitable endeavors. Chances are, that skill field will be lost in America and/or move overseas. That's what happened. Skills and industries needed to provide for the national security supply chain have been allowed to atrophy for decades. America has given away many of its competitive advantages to competitors and enemies so a swarm of Globalist locusts could increase their wealth by driving down the standard of living in Developed Nations.
You've reaped what your policies have sown, you DC dimwits. I hope the cheap(er) sneakers and iPhones are worth it.