In other words, you get people choosing whether to be the care-giving underclass or the class of leaders. Instead of these roles being socially imposed based on biology, as they have been in the past, they are consensually chosen
That will never happen, and would never work. Women are socialized to enjoy their oppression, and while a lot of women are masochistic, sexually submissive and think that's empowering and their own choice ... not all women are.
If society stopped socializing women into subservience, and socialized everyone to be whatever they want to be ... then no one would want to be oppressed, except a few statistical outliers. Males would not witness misogynist oppression that they could then fetishize, so the number of autogynephiles would sink drastically.
It just doesn't work like this, and that's why the genderist worldview is nonsense.
The only way this might work is if you oppress everyone from birth, by default, and give people the option to buy themselves out of oppression.
That's how the US operates - many poor US Americans "choose" their poverty by voting republican, thus ensuring that they don't get healthcare and a minimum living standard, in the hopes that they can join the oppressor class one day, and then won't have to pay taxes.
But for this to work, you cannot let people join the oppressor class just like that.