I don't have the problem the author describes with going into a store and finding games that only have scantily-clad women in minor roles. Perhaps this is because I buy PC mostly games, not console games?
These are the current bestselling PC games, copied from the first page of PC Bestsellers on Amazon:
Lord of the Rings: Shadows of Angmar
Command & Conquor 3: Tiberium Wars
Elder Scrolls IV: Shivering Isles
World of Warcraft Expansion: Burning Crusade
The Sims 2
The Sims 2 Expansion Pack
World of Warcraft
The Sims 2 Celebration Stuff
STALKER: Shadow of Chernobyl
Silent Hunter: Wolves of the Pacific
Baldur's Gate 2: The Ultimate Collection
Sim City IV: Deluxe Edition
Microsoft Age of Empires 3
Crazy Machines: The Wacky Contraptions Game
There aren't any adventures on this list, but I could definitely while away some happy hours playing the Sims or Sim City IV or Age of Empires 3 or Crazy Machines. I would be surprised to find only scantily clad minor female characters tagging along behind fully developed (and fully clothed) male heroes in any of these games I've just mentioned.
My own personal "take" on why young adult women don't play games (older woman clearly ARE playing games -- I'm not sure about young girls) is that they don't have time to learn the intricacies of "hard core" games.
There's a learning curve to a lot of these games, and if you are working and/or or taking care of young children plus keeping house -- you just don't have time to learn how to manage empires or large cities or complicated machines or go on months-long RPG quests. You're more apt to go online for an hour every once in awhile and play bridge or a puzzle game -- something where the interface is easy and you probably already know the rules.
Providing young adult women with a house that cleans itself would make gamers out of them faster than eliminating Grand Theft Auto would.