How do you mean about equal earning potential, though, number? Because, say for the sake of argument that DH and I were both doing what I do, were the same age, were doing equally well right now. Would we have the same earning potential? Well, you could say yes, we do, we're trying for jobs that have the same salaries and equally likely to get them.
But, statistically, we know women tend actually to end up earning less in the same jobs, and not progressing up the career ladder - and it isn't because all of them decide they want children so they will go part-time. Even women who don't have children suffer from this effect.
So, by 'equal earning potential', you'd have to mean a woman in a better job than her male partner, or who was much better at it than him (or older, so further up the ladder?), right?
I'm sure there are couples in that situation, but it seems to me most of us won't be.
Separate issue - but something that I think matters a huge amount is that, if someone like me or mystery decides to have kids, we can plan all we like and both of us can say 'oh, yes, I want to go straight back to work and DH will stay home', but we can't know we will be fit to do that. If a man's partner has a child, that man knows for certain that nothing in the process of childbirth is going to make him unfit for work. Sure, all sorts of unforeseen things could happen, he could end up a single dad with a baby, or caring for a child with needs that hadn't been anticipated. He will certainly end up knackered.
But a woman goes into it knowing there's a chance she'll end up having major surgery or complications, and knowing there's a chance she'll get PND.
At the moment, the structure of a lot of workplaces (all?) just isn't geared up for that. Devey's language about depression shows her ignorance here, and her language about women 'putting their partner and children first' suggests that's the only possible reason women don't get back into work. But what about those women who're forced, for medical reasons, to put themselves first and to take time to recover from an illness? In her world view, these women either don't exist, or she's subsuming them into the category of women who 'put their partner and children first', as if women looking after their own health were actually doing it for someone else and therefore culpable of failing in the business world. That's pretty unpleasant, IMO.