This is what the US’s defense production act is for. If a company makes a critical product, the US has openly stated that it will compel a company to prioritize making that product in times of need. They can’t refuse. This is also why the US wants all of its key systems to be US made- they cannot be held hostage by a foreign entity.

There’s obviously a few areas where this isn’t really true, like a foreign company setting up a US company to sell their product, but by and large the US is immune to the risks you describe. China similarly makes most of their own systems and is mostly immune. A large scale WW3 between the US and China cannot be stopped by a company refusing to participate.