There actually was quite a difference between earlier automobiles and those of the 1930s. But time still makes these “streamlined” ideas a bit amusing.
The principles of reducing aerodynamic drag (streamlining) were well-established in the 1930s. But streamlining of automobiles showed only minor stylistic changes (e.g., teardrop headlights, swept fenders). The upright windshield and rear end of the automobile still created significant wake and vortices.