I agree but with a caveat, it's largely a result of BAD just-in-time manufacturing. Zero inventory production systems (ZIPS) are what people often mean when they talk about JIT, they are different. Toyota, one of the originators and leaders of JIT/lean has not had this problem...because they don't blindly ZIPS [0].

Not holding inventory is great for a lot of reasons, but it is a calculated risk...Toyota learned from experience that if they want to do it, they need to understand risk all the way up their supply chain. They largely aren't having this problem. They de-risked certain things because they really treat TPS and everything associated with it as a philosophy not a set of heuristics that should just be implemented blindly. Manufacturing something is all tradeoffs...there is (almost) nothing with a universal upside. Sure I want to hold less inventory, but JIT is actually about manufacturing time, not inventory. If I have NO inventory and NO ability to get inventory my manufacturing time goes up while I wait with my thumb in the fertilizer pipe.

I've worked with a couple of manufacturing plants (and consultants...) that treat 'JIT' inventory management as something that can simply be pushed off to vendors and then the upside of less inventory enjoyed. They have specs and forms and certification and paperwork...but nobody looks at it. Those are the companies struggling now. They outsourced without fully understanding the risk of the outsourcing. Usually this doesn't bite the world, it bites one or two companies that relied on a certain part (someone misses an EOL notice) or a certain vendor (who goes bust because the owner's grandson ran the thing into the ground). It's like my students who make choices in the first week of the semester that seem minor...and then are frustrated when it effects their grade at the end of the semester (sorry, too much grading this week)

[0] https://www.autoblog.com/2021/03/09/toyota-how-it-avoided-se...