When a collapse comes, components will be unassembled
So we do we have some surplus inventory,but as little as possible due to JIT inventory practices. These are usually components and not many finished products. Let's say it's an inventory of semolina flour, but not packaged noodles. It might be loose leaf tea, but not boxed. It might be transistors, but not radios.
Some many be components of a car. Say that you have axles for pickup trucks, or suspension systems. Those alone would be useful for repairs, but only on specific models as many are not interchangeable.
Those unassembled parts or components of subsystems, even the actual subsystem like a complete power supply for a particular laptop, won't do many people good. Sometimes they'll be edible items and so they could be used, but other times they'll be chemical compounds of say antibiotics, and so of little use without complex manufacturing processes to assemble them, and lots of workers at various stages. Certain industries in a collapse that produce essential items will be of a high value. Other like Ipads? Well, if you can't eat, or have clean water, or electricity, will you need one?
So surpluses exist in pockets around the country. Some will go bad from sitting and won't help anyone. Others will simply sit, and if order is restored, then they can then be assembled.
That will only happen with human labor. We don't have robots to assemble them, over see them, package them, and ship them. Since many people might conceivably die in a collapse, many of these might sit for a long time.
If there is no order, than there's little chance that a complex manufacturing process will gear back up. They all require utilities, manpower, and many other forms of infrastructure to ensure security and supply chains.
If there's military order, then you can bet that will also mean a move to support the military apparatus as a first priority. Then critical infrastructure like health, food, utilities (natural gas, electricity, water), and all the industries that feed into those areas.
If it's civilian, and supported by the military, then it will be prioritized in ways that feed both administration and the military, and communication.
If it's dog-eat-dog and chaos, then it will be a grim time and probably never come back in its present incarnation, and revolution, good or ill could result and massive deaths.