To me, that graph looks like the tech industry transition from hobby to industrial/business tool. Pre-1985, there weren't many colleges even offering computer science degrees, so any data from that era could easy fall apart due to small sample bias.
I don't think anything necessarily "happened" to women in tech. You could just as easily say that as computer science became a more established field, men swarmed it because it was interesting to them.
I don't think anything necessarily "happened" to women in tech. You could just as easily say that as computer science became a more established field, men swarmed it because it was interesting to them.