Rules and lore complexity certainly play a minor role in the missing appeal of p&p games for women. What keeps them away is that the scene is populated by people who look like Mearls, a classical neckbeard, and are so socially inept that they try to white knight by insulting women's intelligence and ability to appreciate richness and complexity.
kek the only women I know who play non-storygame rpgs play pathfinder.
Simply put, the number one thing that has turned them off from playing table top rpgs, and this is me asking them today, around 16 people:
1, 2 and 3: A morbidly obese neckbeard who acted all feministy and shit and was overwhelmingly nice to them until he asked them out at which point he grew ridiculously hostile to them when he was rejected to the point where he'd randomly attack their characters mid-battle or try to rape them in the game.
4: An obese racist trump supporter who got the "kekistani" flag tattooed on his chest and constantly asked her what her political opinions are
5 - 9: An obese man who looked like a medieval polish villager whose complete and utter ineptitude at playing, running, or being nearby tabletop games, taking actions in the game personally, getting mad at people for not doing what he wanted, and sometimes just outright hostility(like ripping up his campaign notes, balling them up into a ball and bouncing them off one of their heads for sneaking past an encounter and then screaming at her and telling her if "she was so fucking clever, maybe she'd like to do his fucking homework and suck his dick")
10 - 12: Guy who roofied a girl at a party a few years ago showed up and when pressed the man admitted it and cracked jokes about it and the DUngeon master called them "SJWs" for wanting him not being allowed to play
13 - 16: guy would not wash himself, constantly had his hands down his pants and usually smelled like shit. tried to fuck one of the player's preteen daughters, and the rest of the male members of the group told her she was being a "bitch" for not letting a 29 year old neckbeard date a 13 year old