I still agree that CS being "less social" is a huge factor. But have to admit it seems like there's some other factors too, and I think the "less social" and "wild west" combo is pretty significant.
I actually think this is probably wrong. Back in the day there was a higher percentage of women in CS. It's possible that in absolute numbers there are as many women today in CS as there was then. That's because there's probably a lot more people in CS overall.
I also think it's likely that back in the day most college-educated programmers had EE degrees, not CS degrees, so what you'd really want to look at is the percentage of women in CS and EE, not just in CS.
The professor I was thinking of was a woman, actually.