Final answer:
The major disadvantage of mass production from a downstream value chain perspective is a lack of flexibility. This is due to the standardized production processes which can impede adaptation to new market demands or customization.
Step-by-step explanation:
From a downstream value chain perspective, one of the major disadvantages to mass production is lack of flexibility. While mass production can lead to reduced production costs and increased efficiency due to economies of scale, it can result in a drawback when it comes to adapting to changing market demands or customer preferences. Mass production systems often struggle to switch between different product types or customize products to individual specifications due to the standardized nature of production processes.