Modern cars all the same to you? Look at this

This is a great point. I would really say that probably, the mid 1950s to late 1960s was the most unique in terms of automotive design where cars and paint jobs could be told apart. Especially the two tone paint jobs of the 1950s. From 1930s to 1940s we really saw zero innovation because of the Great Depression and World War II that stopped auto production. The mid century post war economy really changed things. 1960s would call my favorite decade of automotive innovation and design that introduced the Corvette, Mustang, Camaro, GTO. You could tell these models apart from one another. Not just different models, but we saw big changes between model years. A 1963 T-Bird compared with a 1964 T-Bird for example. By the mid 1970s American cars started becoming more or less monotonous in design again and it only got worse in the 80s and 90s. A lot of it being that CAFE emissions laws basically mandated that autos have to include foreign parts to compete with the Japanese. Imports did not have to meet the same mileage standards as American vehicles. Prime example is Crown Vic LTD compared with Crown Vic that more or less looked like every other 90s import on the road. Now that we factor in pedestrian safety edges have to be rounded off.

From the mid teens and through the twenties the American car companies seemed to concentrate on cheapness . For example they had very little or no bright work, even on the more expensive ones. Then in the thirties the focus changed to styling and there was a race on to make beautiful cars. Aerodynamics became part of this. Even the inexpensive cars were stylish. The 1936 Ford is considered by many to be one of the most beautiful from this era. Ford was so serious about having a beautiful car he had an outside designer style it. He was a famous yacht designer. This could be the only Ford styled by an outside source.

Have you noticed that the yellow Hupmobile has the same body as the late, lamented Cord Beverly and Westchester models? Hupp and Graham used the body dies after Cord closed down.

I would not agree that all British cars of 1939 looked alike. M.G., Rover, Morris, Riley, Austin, Bentley, Singer, Triumph, Vauxhall were pretty distinctive. But even in America there was more choice of body styles than the models would suggest.