" High heels are uncomfortable and make walking more difficult. Prolonged use can injure the feet, knees and back. So why do women keep wearing them?"

I have never officially researched this question. BUT, my answer would be something along the lines of a 'slave to fashion' type answer, and further clarified by my own personal observation that many women do not wear heels routinely anymore. I am in Uggs today, again. LOL.

Put it in the same category as hosiery. I am nearly brought to public comment when I see another female in court sans hosiery! But, she might think me a bit odd if I said, "wow, it is so nice to see another professional not wear hose!". I secretly think it, though.