"Between two products equal in price, function and quality, the better looking will outsell the other" (Raymond Loewy)
The economic success of industrial design came in the 1930ies. After the Wall street crash in 1929 manufacturing companies saw competition rise to an unprecedented extent.
Design was discovered now as an advance in sales, the aerodynamics of planes were transfered as an allegory on many consumer goods to suggest speed, technology and modernism in general. An important role in "Streamline Style" played a new material: "Bakelite" was one of the first plastics to be used extensively. It's malleable properties were the perfect expression of the smooth, sleek contours of a streamlined product.
Today this promise of a dynamic future looks superficial because the focus was not mentioned on technology or the relationship between the object and its environment.
The theatricality was applied on all consumer goods and made them attractive in a way that everyone understood.