(1) It made me wonder if there was an actually scientific way of tracking these things over the years. I imagine there's something buried in social surveys? It wouldn't be the same but might be a little informative.
(2) I was expecting a discussion of a different topic, and am not really sure she addressed the comment. The comment explicitly begins with "I'm referring to attitudes while dating, not how receptive someone is to having sex" and she seemed to discuss receptivity to casual sex.
This is fine, it's not really a criticism although I think the topic she seemed to lead with and that the commenter was mentioning seemed more interesting to me. I'm not sure I agree or disagree that dating norms have changed, but if it did it would be extremely interesting to me.
I've read a lot of women mention that when or where men are being pushy or manipulative, they tend to be more defensive or proactively self-protective like she's saying. I don't think I've read as much about an idea that women are "playing harder to get" in an established (in a broad sense) dating relationship. I'm a bit skeptical but it's interesting to think about changes over time in these kinds of things. At least in the US I feel like the focus is a lot on changes in cultural norms around sex, and less so on relationships per se.