Part of the problem is taxes. I retired from Boeing a couple years ago, so this is fact. Washington state taxes you on inventory every quarter. Big companies came up with JIT, just in time. If we only had one black box in inventory, it saved in state taxes. Unfortunately, if the box failed functional test, we were screwed. It took a month, at minimum, to get a replacement. The production line doesn't slow down or stop. We had dozens of aircraft(747's), waiting on the flight line for a couple of parts. Boeing bit the bullet and had at least 2 in inventory to get the aircraft delivered to the customer on time. Companies keep minimum inventory so they don't get stiffed by state and federal taxes. JMO.
