[SPSteinbeck]

There's no strong reason to suggest that this difference is due to anything other than social pressure.

The fact that such social pressure to enforce gender roles exists and the fact that such pressure independently arose in every advanced civilization to ever exist overwhelmingly suggests it is an intrinsic feature of the human race. Certainly, this would suggest the only way to overthrow the gender roles you despise is for some governing apparatus to coerce behaviour (which we already do to some extent); organically, humans will organize themselves in what you would call a "sexist" way.

Of course, even then, the shelf life on the sexless world you envision is short. American hegemony is waning and none of the candidates to fill the power vacuum will have much time for the 'isms that so occupy your mind.