Women recently became the majority of medical doctors. Are they devalued? Same deal for lawyers. This line of thinking doesn't hold up to scrutiny.

A more plausible explanation is that men prioritize earnings more than women. The reality is that most women still expect to marry a man that outearns them. Men are keenly aware of this understand that their marriage prospects are reduced if they don't get a well paying job. Hence why men tend to take riskier jobs, and jobs with longer hours.