“JIT” as we called it back in the late 80s and early 90s when I was involved in cost containment for a phone company, was used to reduce millions of dollars of inventory from being held over fiscal year thresholds and other accounting bogeys. Inventories cost money. Monitoring them and turning them over accurately in response to customer needs is a lot of work, but, I suspect, basic business-101 today.
It takes training and a certain talent to make everything come together at just the right time and place for production to happen. You also need to know what you should stockpile in the backroom in case of emergency.
I remember the implimentation of JIT. Good for a peace based economy but dangerous and foolish for a war time economy. Our economy should be focusing on stockpiling and defense here in the states. More like Swiss, less like Americans