I can see the change in gender ratios in the 80s being highly correlated if not partially caused by the move from an East Coast Organization Man (or Woman) industry around Route 128 with companies like IBM and DEC to a West Coast Hippie Homebrew industry around Silicon Valley with companies like HP then Apple.
When the industry moved from the east cost Organization Man (or Woman) operations, the computer science and engineering career largely fell off the map at Universities.
Up until ~93 (the year of the IBM layoffs) colleges and universities were grooming you for Organization Man (or Woman) career companies like IBM, DEC, GM, Ford, Chrysler, GE, Philips, AT&T, Shell Oil, Exxon, etc.
When tech stopped being an industries made of career companies, it became a fringe industry that you only knew was viable if you knew people making a living in it. At that point we have an industry that grows far more slowly based on Granovetter's strength of weak ties and far more rapidly based on strong personal hobby interest in subject matter such that you end up learning about the myriad companies in Silicon Valley well before there was a tech media like Wired and TechCrunch standing on roof tops and declaring a gold rush.
Before Wired magazine, no one without an already strong personal interest in computers and software really knew anything about what was happening in Silicon Valley. It was essentially non-existent for an entire generation (X) and most of a second generation (Y). It's only with Millenials that Silicon Valley has been considered a good career path for those with capital in terms of technical aptitude/competence, but aren't hard core computer nerds.
I'm curious how the engineering gender ratios evolved for companies like IBM and DEC versus HP and Apple from from 1970 to 1995. Now with those figures in hand, I'm curious what impact layoffs and workforce reductions at IBM, DEC and other highly visible traditionally Organization Man (and Woman) companies had on the industry ratio and the visibility of women in the industry.
I was born in the early 80s and my formative years when I would have been thinking about "what I want to be when I grow up" were basically the mid 80s to the mid 90s. At the time, I had exactly one engineering role model from elementary school to high school, an engineer at Philips, despite the fact that I grew up in a reasonably affluent town about a 30 minutes from the IBM headquarters in upstate NY. Computer Science wasn't even on the radar career wise. You were encouraged to become a doctor, lawyer or business person. If you were interested in companies like IBM, you were encouraged to want to get an MBA and be on that side of the social divide in those Organization Man (and Woman) companies, because the engineering side wasn't considered a path towards affluence for the systems thinking gifted like medicine and law were.