Japan is notoriously mineral-poor, so they had to put in extra effort that is not necessary with better raw materials. Further, I suppose this scarcity means t

Japan is notoriously mineral-poor, so they had to put in extra effort that is not necessary with better raw materials. Further, I suppose this scarcity means that swords become more of a prestige item, meaning that you can put in more effort when manufacturing one. In contrast, when decent steel is cheap (relatively; we're still taking pre-industrialisation), then you might do something more akin to mass-production.