Let's start with men in business suits - why are 95% of dress shirts white? What are men so timid? Why are bowties, string ties, and cravats so rare?
I wonder why the necktie hasn't disappeared altogether? They serve no purpose (originally they were used to hold collars closed, at least), restrict blood flow to the brain, and are incredibly uncomfortable.
I recall with great fondness a lecture I attended by Jon Bentley, in which, using a set of viewgraphs, he put one up with some AWK code on it. He started to describe it, but began stammering. He stopped, took of the necktie he was wearing, smiled, and moved to the next viewgraph, on which was written:
It is impossible to understand a computer program while wearing a tie.
He then went back to the previous viewgraph and continued.
Brilliant man, that Dr. Bentley.