My favorite hard slogs are the zipper and the cotton harvester. The former took something like 30-40 years to develop and then no one wanted it. The latter took 100 years of tinkering.
Yeah and zipper was the result of trying to design an mechanical Hook-and-eye closure. Which look nothing like a zipper. And definitely fits the articles point that somethings couldn't be made until all the supporting pieces were in place.
A lot of inventions were initially hand crafted and then automation was applied to reduce cost. Think sewing pins. For zippers automation was necessary from day one. As you said hard to make. Likely cannot be made by hand.
