Durability, quality and reparability. Most fabrics build today are so fragile and needs to be replaced soon, despite the advance in material and weaving.
Most highly qualified workers loves what they do and would stand for keeping they’re output quality up. On the contrary interchangeable cheap workers have no real incentive to that. The factory’s manager is left alone in charge to balance quality versus cheapness, and the last comes with obsolescence (planned or not), which is good for business.