IE, BMW also followed the German Mondern principles as taught at the Bauhaus.

I'm not talking about "style" here -- it really has little to do with the style of the vehicle or any of the signature details. The Bauhaus school in Dessau was probably the single most influential art/design institution of the Modern Movement. Great emphasis was placed on conceiving objects to be produced by machines (lessoning the requirements for manual labour). This, and the strict principle that an object should express its purpose (its function) through its appearence (the aesthetics of functionalism) were of paramount importance. There was also a deliberate intention to create objects which expressed a new "Machine Aesthetic" -- objects to be produced by machines, designed with no superflous decorative details -- reduced to essential functionality (Less is more) and expressing the new industrialized world. These tenets influenced western design for most of the twentieth century -- things started to get more experimental in the 1950s but it really wasn't untill the mid 1960s that the Post-Modern revolution in design started to break with these "rules" of Modernism.