Not so much a “secret” history as a suppressed and forgotten one. The shift began in 1984…and as software development starting bringing in bigger money than hardware development.
From the Article
“At the same time, the old hierarchy of hardware and software became inverted. Software was becoming a critical, and lucrative, sector of corporate America. Employers increasingly hired programmers whom they could envision one day ascending to key managerial roles in programming. And few companies were willing to put a woman in charge of men. “They wanted people who were more aligned with management,” says Marie Hicks, a historian at the Illinois Institute of Technology. “One of the big takeaways is that technical skill does not equate to success.”New York Times Magazine: The Secret History of Women in Coding
“By the 1990s and 2000s, the pursuit of “culture fit” was in full force, particularly at start-ups, which involve a relatively small number of people typically confined to tight quarters for long hours. Founders looked to hire people who were socially and culturally similar to them.”New York Times Magazine: The Secret History of Women in Coding