Because Japanese hand tools are objectively less efficient than power tools in a carpentry shop. The guys that want to use hand tools can go work in a boutique that charges a premium for that level of craftsmanship. If you told them to use power tools, no amount of utility would convince them to use them, with most of their justification being psychological. Also, "It is difficult to get a man to understand something, when his salary depends on his not understanding it."