But if the optimal strategy only falls apart for uncommon events that you can't determine when they happen, how much of an incentive is there to run a conservative/gambling strategy like that?
Look at companies like Boeing with absurdly complex supply chains. The inventory numbers look good, but the factories are idle when a truckload of magic bolts is stuck in a blizzard in South Dakota.
It also increases actual cost. I supported a GE business unit as a supplier for awhile. We hosed them for stupid last minute orders due to this sort of thing. They would pay more for expedited shipping, overtime, waste money on leasing stuff to avoid capex, etc.
Maintaining resilience and designing antifragile systems usually pays off in missed disasters and unique opportunities.
Alternately, to save money without buffers is to continuously gamble.
For example COVID style shutdowns could be reasonably modeled at X% per year after talking to a disease specialist. But, not all of them are going to be from diseases.