This is a balance point, not an optimization problem where you're supposed to go to the extreme.
In fact, one of the books that popularized Lean manufacturing, Eli Goldblatt's "The Goal", explicitly makes the point throughout the book that making work centers within a plant locally optimal will cause your overall operation to fail to deliver efficient outputs.
To make global efficiency improvements you have to accept that individual work centers may be inefficient. Rather, just like a developer optimizing their software program, you need to look at your entire organization and find where the actual bottlenecks are, and improve those specific bottlenecks, potentially by running "inefficient" (but non-bottlenecked) work centers to assist the teams that are the current bottleneck.
And then as you change things you'll have to be willing to address a different bottleneck.
Moreover, unavoidable variances (which the book describes in a story about a Boy Scout camping trip) means it will be potentially disastrous to 'optimize' even your critical path, just like you wouldn't want a network router to be consistently near max capacity.
Turns out it's Goldratt. Very difficult to read as it is in the form of a melodrama. I suppose the point was to make it light reading, but to me it's a difficult slog through the protagonist's personal life to get to the data I want.
And what exactly is a big stockpile of raw materials and components that aren't intended to be delivered to the customer under normal circumstances?
It's important to remember that in traditional manufacturing at the time, each work center wasn't graded on its ability to contribute to customer sales, they were graded on things like local efficiency on a per sub-assembly basis. The "customer" wasn't the end user, the "customer" was the plant manager or the PMO or some other stand-in.
The work centers were structured around functional tasks like "heat treat" or "machining" rather than an end user product, so your "high priority" customer product had to make it through multiple independent backlogs before it could be shipped, even in theory. God forbid rework would be needed! Quality issues were the job of customer service to address, not the work center that introduced the defect (as after all, it might be years before the sub assembly finally ends up in a user's hands).
To be honest I would recommend a separate book for software practitioners, Reinertsen's Principles of Product Development Flow, because it gives you methods to look at which are more applicable to creative work where you can't easily turn your work into "production lines" to then use Lean manufacturing/JIT principles on.
Either way none of this works if you let every local work center just produce produce produce up to its peak output or most efficient point. At that point it becomes impossible to find the bottleneck because there are so many bottlenecks (including bottlenecks not on the critical path). That's a key reason why all the methods (Goldblatt, Reinertsen) focus on reducing the amount of work-in-progress and reducing batch sizes of each individual work package or work item.
Personally I have been ranting about the Modern use of Just in time manufacturing for well over a decade. Just in Time manufacturing as it originate in Japan doesn't actually means no buffering. Somewhere a long the line in typical Chinese whisper fashion the true meaning got loss when it go to the west. If you are software developer, just like at Agile and Kanban board.
The problem make worst when CEO and COO dont actually understand this, and force those in supply chain to comply with their view of JIT. It works in a sense when everything is normal. It doesn't work when there is a shock. Look at Apple, the only company that took JIT to a level beyond Toyota. They are doing just fine while others are fighting for parts.
The other thing worth pointing to is that this isn't just chips, but also every other commodity. The reason behind all these different industry are exactly the same. You could have swap the title for Beef, Poultry, Steel, Toilet Paper, Mask, Chips, Milk, Pencil, paper etc... I really do wish people learn a little about how supply chain works. It is the fabric of our daily life and yet very little attention has been paid to it.