Factories need the 10 nails a day option, because factory tooling is custom, and tooling for high-tech has extremely low tolerances, so those 10 nails need to be custom and perfect. Often they also need to be certified/constantly calibrated by the nail maker.
When I was in aerospace management decided to move our fixture guy to a part time contractor instead of meeting him on his salary increase request. Almost every step of the factory other than some sub-assemblies were dependant on the fixtures, the fixtures needed to be constantly re-calibrated, etc. And there was no other fixture guy in the area. We fired like the most important person in the entire factory and hoped he'd stick around for part time contract work. I was no longer working there before it happened, but the first time a fixture needed calibration but he had other contract work, that whole section of the line is down at like $200,000 a day until he can come in. Like OK you scheduled him for the normal maintenance, but what happens when a forklift hits a fixture and he's off at some new clients site for 3 weeks? Or the AC goes out and the heat takes everything out of tolerance before you get it cooled off again.
And with JIT manufacturing having fixtures down throws off the schedule AND you don't have capacity to catch back up because you have capacity for the barest minimum you can get away with. These guys are very very important and yes it is terrible if we don't have their skills available on demand.
The management thinking from your example seemed very natural and not so surprising after all. They just needed someone with a "just in case" mindset, similar to the tailor from one of my favorite scenes/movies "The Hudsucker Proxy" - "The Double Stitch" [0]. I even sometimes act like that character. For example, when the boss says we will drop a feature, I don’t fully kill it, instead, I temporarily disable it because the chances of it coming back are not zero.
When I was in aerospace management decided to move our fixture guy to a part time contractor instead of meeting him on his salary increase request. Almost every step of the factory other than some sub-assemblies were dependant on the fixtures, the fixtures needed to be constantly re-calibrated, etc. And there was no other fixture guy in the area. We fired like the most important person in the entire factory and hoped he'd stick around for part time contract work. I was no longer working there before it happened, but the first time a fixture needed calibration but he had other contract work, that whole section of the line is down at like $200,000 a day until he can come in. Like OK you scheduled him for the normal maintenance, but what happens when a forklift hits a fixture and he's off at some new clients site for 3 weeks? Or the AC goes out and the heat takes everything out of tolerance before you get it cooled off again.
And with JIT manufacturing having fixtures down throws off the schedule AND you don't have capacity to catch back up because you have capacity for the barest minimum you can get away with. These guys are very very important and yes it is terrible if we don't have their skills available on demand.