Staring at the chart, 1980 doesn't seem that significant. It shows from 1970s to 1980s, almost every major has seen an increase in women graduates.

I don't know much about this subject, best I can do is pass around a link(video) I saw that was semi-convincing to me that - there might be some general biological tendencies(https://youtu.be/p5LRdW8xw70). Biological tendencies are not useful for individual cases, so as long as everyone is given moderately equal chance at getting a job they qualify for and can do the work in peace, everything is well and good.