Everyone has their theories but I think at least part of it is generations and fads, everything from perms to big hair to beehives, etc. Lately straightening your hair seems to be the rage. It shows as far as mass media whether it is TV anchors or sitcom stars. I don't see too many curly-haired TV anchors. As for the work environment it can depend but any company that forces you to straighten your hair though (by rule or implied) is one I have very little respect for.

"Curls aren't just for girls."