Have you checked out our Remedial Math page? Women writers deserve to be paid for their work: this means they deserve bylines, they deserve critical attention, they deserve tenure track jobs, etc., and they are not receiving these things in any kind of fair proportion.
I don't think there's much ethereal or philosophical to discuss here: it's just about the numbers, plus that simple and no longer radical concept of equal pay for equal work.
I think that until you start counting bylines you just don't quite notice the major imbalance.
So try it today: how many women and how many men did the New Yorker give bylines to this week?
The weird thing about counting is that women's presence somehow hovers around 20-25 percent across the board, from the New Yorker down through the upstart lit magazines. It's often worse at Harpers and the New York Review of Books--the more hoity-toity, the more boys school.