"Little more than a century has passed since women began to work in offices. "
Actually women began to work in offices well before 1920.
While it's true most women stayed home, the decline of the family farm that began with the Industrial Revolution sent many young people (both women and men) into the cities, primarily into factory work, but office work began to develop for women after the invention of the typewriter (post Civil War).
It took a while to both the machine and women to become the norm in office work, but it wasn't long before office bosses figured out that women were much more adept at office work than men because they were more detail oriented. Plus social rules for middle class females required that they not be married, so the majority were single, usually responsible only for themselves (or so it was assumed) and therefore could be paid less.
Imagine that. Getting better workers for less pay.
One job they had was actually called "Typewriter," named (obviously) after their primary office tool.
The two world wars changed all that, as women, married or not, had to replace men drafted into the wars. The women were expected to return home so that returning men could have their jobs, and that didn't sit well with more than a few of them.
....Just a side bit of detail.
I'm afraid your sort of what I call a "sappy happy" version of women in the workforce, with no men pressuring women "put out" or lose their jobs, is not and never has been the norm. But hey, it's a nice fantasy.