The longer the chain, the more arduous the task of delivery
Imagine living on the West Coast of the USA. An earthquake strikes. Supplies are needed, and the products are far away on the East Coast of the USA. The people on the West Coast not only need those supplies, but they also need personnel to install, maintain, or teach or facilitate their use. Those personnel live elsewhere, but must be brought to the West Coast as well.
It would be easier of course if the personnel and supplies were closer, and this is why duplication of inventory and training of personnel is done to facilitate operations. Still, that requires a lot of foresight and money and the will to apply energy towards both purposes.
We all know that most people will do the least that they have to, for they're busy with their regular activities and use minimal energy for preparedness for something that happens irregularly.
This means that disruptions in a disaster are normal, but shocking for the person experiencing them. They thought is couldn't happen to them because their routine lives are relatively simple because of mutual co-dependency.
That co-dependency creates the potential for an equal disaster should something break the chain of mutual assistance.
The further away the supplies and personnel are, the more expensive the transportation costs will be in fuel, time, wear and tear on vehicles, cumulative personnel's downtime (breaks, sleep, refueling), traffic jams, detours, etc.
The weather will create stoppages of work-flow. Sometimes, the stoppage could entirely halt multiple vehicles and back them up if the sole channel for transportation is disrupted. See issues of barge traffic along the Mississippi River due to drought. It causes a cascade failure. It means river dredging operations by the Corp of Engineers and unloading and reloading of barges.
If supplies are needed in multiple locations simultaneously, then the deliveries that are closest to their end point destinations will arrive first and be installed. Isn't that logical? A delivery of supplies might be diverted towards local effort way before they ever made their way across country.
If a dollar collapse happened, and a driver was attempting to make deliveries and had no way to cope with rising fuel prices, then how would the driver get to their destinations?
Wouldn't you rather have a month of supplies (minimal) and learn skills so you can cope yourself rather than wait for something to arrive and suffer in the interim? If people didn't have food and water for a month, how many would perish? All of them would that didn't have skills to acquire food and water.
In a month after a collapse, a lot of food might be around in distribution centers unless they've been commandeered. Survivors of any collapse could probably locate some supplies amidst all of the wreckage left behind of such chaos.
Based upon the agricultural season, mass amounts of crops and livestock could die or be rendered unusable. Don't count upon them as being food sources.