Yeah, the original comment is way off. I worked for a major electronics manufacturing company helping with demand driven MRP (DDMRP, MRP=material requirements planning) and obsolescence (DMSMS - diminishing manufacturing sources and material shortages).

I can definitively confirm that just-in-time is about trying to optimize the amount and strategic positioning of buffer needed to support the "right amount of production" to meet anticipated and actual demand, exactly as you describe.

Now, doing that can be rather difficult in the case of black swan events. But the goal is as you describe.