Traction devises were very popular in the 1930s and there were many patented including HAV shields and arch supports. The demand came from the physical fitness fad which followed the Great War. The major 'political' concern at the time was the general level unfitness of young men to serve their country in the case of War. Hence governments encourage the physical culture in every way including medicalising flat feet.
Post Depression, nutritions levels and poor and people took to all manor of physical activities (usually because they were social and did not cost money) to keen their spirits up. Marathon activities of all kinds from running (the Bunion Derby), roller skating, and dancing (see They shoot horse don't they),
took the conscious attention of the Western Populous. In Germany physical cuture became a National obsession and many of the patented foot devices come originally from that country. Most eventually sold well in the US. ;)