I’m not convinced this is necessarily true. JIT implies making all of your buffers more obvious, and you will want to reduce unnecessary buffers to save cost, but maintaining some buffers for the sake of resilience isn’t incompatible with JIT supply chains. The problem comes when you combine short-term oriented management with JIT supply chains; if you quantify the cost of a buffer, you make it easier for that type of management to make that kind of decision.

Toyota, for example, is one of the firms that popularized JIT, but they don’t usually run into the same short-termist problems that afflict other firms. Relatedly, Toyota’s senior management have all spent decades if not their entire careers at Toyota and still includes members of the Toyoda family. Those guys are probably not going to play fast and loose with resiliency just to make quarterly numbers look good. They are going to look at the quantified and understood cost of their resiliency buffers and say, “removing this buffer might save lots of money next quarter but in the long run that represents a risk to a company I intend to pass down to my grandchildren so I won’t do it”. Whereas a different manager at a different company might say, “this will definitely make the next quarter’s numbers look amazing and if there are consequences in the long run, either I’ll have switched companies or I can just say it’s not my fault”.

Is it really 100% bad? Do people really think that the goal of humanity is to work in the most efficient way to extract the most economic value from everything possible? Can't we just be content being 50% efficient and use the other 50% of that effort to chill with family and friends and talk about films or something?