To partially answer your opening question, I think it's because there is a direct correlation between build quality and sonic quality, especially in speakers. Cast baskets over stamped, braced cabinets over unbraced, short coil/long gap over long coil/short gap. And these features cost more to source for the manufacturer, and thus are reflected in the price.
For electronics though, the range of build vs. sound quality is very wide, with progressive US companies such as Schiit, Wyred 4 Sound and PS Audio, to name a couple, offering very high value, build and sound quality components.
For electronics though, the range of build vs. sound quality is very wide, with progressive US companies such as Schiit, Wyred 4 Sound and PS Audio, to name a couple, offering very high value, build and sound quality components.