But my question is, does PUA theorizing help him get an accurate model of what women in general are actually like? More generally, does it give him tools to get a better understanding of what reality is like? Or is it just giving him tools that help him to focus his attentions on a certain small subset of women?

I thought about it some more and honestly can't tell if you're right or not. On one hand, I never do cold approaches - there's always some eye contact and smiling beforehand - so the women I interact with are already very self-selected. On the other hand, I know from experience that a girl who rejected me in one setting (e.g. a party) may often turn out to be receptive in another setting (e.g. a walk), so it's not like I'm facing some immutable attribute of this girl. So every interaction with a woman has many variables beyond my control that could make it or break it, but my gut feeling is that most of those variables are environmental (current mood, presence of other people, etc.) rather than inborn.