in heat treating, there are steps which dont lend themselves well to large quantities due to time constraints, the amount of work involved in each step, tight tolerances, and so on. On the other hand, there are steps which lend themselves very well to large batch heat treating. Depending on the kind of steel, the results you are looking for, etc, the ideal process will vary. Its not magic, just reality. It also generally happens to be true that the more you try and push the limits of the steel with which you are working, the more attention to detail in each step, and the more time sensitive each step is.
Take AEB-l for example... on paper, its a truly unremarkable steel... not a high amount of carbon, no crazy alloying, etc... just a pretty simple steel. I get the sense that people feel like its a super steel, but in reality, its got less than 0.7% carbon, which most users here would generally scoff at. As a comparison, 440c, which is a steel that nearly everyone here thinks of as subpar, looks a lot better on paper. The fact is that both steels have potential to be great (yes, there are good knives out there with composition like 440c), and both can be crappy. It depends on the makers knowledge of the steel and abilities in heat treating. As i said before, you will find that some steels lend themselves better to small batch heat treating (when you are looking for specific results and are pushing the boundaries of what that steel can do), while others work great in large batches.
Take AEB-l for example... on paper, its a truly unremarkable steel... not a high amount of carbon, no crazy alloying, etc... just a pretty simple steel. I get the sense that people feel like its a super steel, but in reality, its got less than 0.7% carbon, which most users here would generally scoff at. As a comparison, 440c, which is a steel that nearly everyone here thinks of as subpar, looks a lot better on paper. The fact is that both steels have potential to be great (yes, there are good knives out there with composition like 440c), and both can be crappy. It depends on the makers knowledge of the steel and abilities in heat treating. As i said before, you will find that some steels lend themselves better to small batch heat treating (when you are looking for specific results and are pushing the boundaries of what that steel can do), while others work great in large batches.