[sandworm101]

Because they are not suitable for many of the tricks used in high-productivity environments. Traditional craftsmen cannot be automated, else they not be traditional craftsmen. Restaurants cannot enjoy the same economies of scale and still provide the same personalized service out of a tiny shop across from a train station.

By another metric, they are low-productivity in that the require many man hours of labor per unit. One can make a carpenter more efficient, but one cannot get away from the need of a person spending hours inside someone's house nailing things together. He;ll never be as productive as an Ikea factory worker churning out flat-pack tables inside a megafactory.