The 3rd influence on worldwide fashion is…

.. Ideology.  The status of women was reflected almost exactly in each era.  In the 18th century they were “trussed and feathered” as they supported their men, late in the 19th they wore “expanding broad shoulders” as they entered the work force, and by 1914 just before World War I it was “anything goes”.

Of course there were hundreds of key fashions in between those including the 1913 suffrage movement’s thin white gowns that got them put into jail.

(Featured: One of the women leading the Women’s Suffrage March in Washington DC at Woodrow Wilson’s inaugeration, 1913; below the march itself)