... writers are required to create convincing characters who are different from themselves. But in video games, writers have tended towards idealized versions of themselves. I take this as a sign of limited ability and of limited ambition, driven by the concerns of marketing. In any case, it is not easy to find a Hilary Mantel or a Joss Whedon or even a Rhianna Pratchett or a Neil Druckmann. (This piece in The Guardian argues for and against the most notable women characters in literature who were created by men, and is worth a read.)
Rather than tackle this argument head-on, I'll start by tackling it sideways, by way of an analogous problem Harlan Ellison complained about in the 1970s: the lack of genuine character in SF, with vanishingly few exceptions. The notion of SF as a literature of ideas could be taken a little too far, it seemed; a lot of the material produced under said aegis made it more like a literature of nothing but ideas. It's notable that most of the big exceptions come from SF in film and TV, and not from literary SF — although I don't know how much of that could be chalked up to literary SF taking a major backseat to film and the tube. (When literary SF gets mentioned at all these days, it's typically in the context of a book that's just been optioned for an adaptation of some kind, and not because someone's championing a book that deserves to be read. Feh.)
Given that most SF&F doesn't do character well, if at all, I'm not surprised most of it doesn't do female characters well, or at all, either. That said, I don't want to assume that's the real culprit; it's more like one symptom among many. Too much of SF has been written for, and read by, an audience presumed to be mainly male, mainly interested in women as objects of one kind or another — even when the people picking up said books weren't necessarily like that. Especially when some of those audience members were women as well.
If there's any particular thing that allows the member of one sex to write the other sex well — or that allows anyone to write anyone that's not close to them well — it's empathy. Such a mushy word, but I'll try and make cement from that slurry if I can. Empathy isn't just the ability to feel what someone else feels, even if their experiences don't map to ours, but the ability to understand what that means, to build a bigger picture of the world outside of ourselves through that.
In short, it's a growth process, which explains why a literature and a genre that has for too long been treated as a growth retardation process has had such trouble manifesting it.