The respect people had for her plummeted because she left at 12 noon everyday and never, ever took on more work even in a crunch. She was upset that she was not promoted. First of all, it really depends on the organization. Part time is sometimes indeed 4-5 hours a day. However, if people are expected to work 12-14 hours a day.
Some organizations have a very supportive attitude towards part-time.
I've seen employees share a job, where each might work 4-5 hours a day, and the combination of 2 employees can often be even more productive than one, because there's less opportunity for boredom and burnout, and employees tend to be more balanced and happier. But to a large extent it depends on the corporate culture. If, as in your business, people are looked down upon or derided for working less than full time, it might end up not being a very supportive environment for someone with those flexible needs. Perhaps women are quitting the corporate climb because they realize that it is not a level playing field and that it will not become one in their lifetimes. After women realize the sheer magnitude of the barriers that they face, they may realize the grueling climb is not worth it because they will never make it to the top or at the very best, they will have to sacrifice their personalities, their beliefs and their ethics to claw their way up in a man's world.