Doesn't this doom all relationships, though? After all, women often want to see "progression" in a relationship as it goes on: exclusivity, marriage, house, kids. At the same time they want to see the guy improving themselves -- successful career, becoming a better person, getting fitter, staying active socially, etc.
But what if one of those phases lasts too long or doesn't go as expected? What if you get the house, and then there's no "progress" in the relationship for 5 years? He's made it to a certain level in his career and life where things are better than they've ever been, but it's a plateau at the top?
Worse, what if he's a real person, and he wants to destress from a 50 hour work week with mindless entertainment like video games by himself? After all, he needs to tackle two full days of house maintenance (cutting the lawn, laundry, shopping, and everything else) this weekend.
Despite things being better than ever, he's "complacent" and just "maintaining" -- not tackling ambitious new goals and trying to self-improve. Usually the result is an immediate lack of attraction by the woman, compouned by the fact that now he's not opening up to you. He doesn't seem self-aware about what he needs to improve on, since he's decided things are "good enough." Aren't they, though? He shown improvement, and is the same person who desires self-improvement, but it's tougher once you've already taken a few steps. Like fitness, there are diminishing returns to self-improvement, and it takes a ton of time.
Of course the solution has nothing to do with the man in the story. Instead of complaining his wife has no sex drive, which is taking the express lane to divorce city, he needs to return to what attracted her to him: his vulnerability, self-awareness, and desire to improve himself.
That's easier said than done, especially given the paradox of choice leaving both partners less happy than if there were only a few eligible mates of the certain age in our tribe of 40 hunter-gatherers (and our 3 neighboring tribes). (See https://www.ted.com/talks/barry_schwartz_the_paradox_of_choice?language=en and https://en.wikipedia.org/wiki/The_Paradox_of_Choice )
It's hard for a guy to want to be vulnerable and improve himself if he's not happy, particularly if he's in an exclusive relationship that's currently sexless. After all, his attraction to her didn't change, because it was shallower in the first place (sorry, but it's true). Guys just don't care as much about seeing their date as vulnerable and self-aware -- they want women to tick those other boxes, like brains & beauty.
Again, though, it's the guy's responsibility to continue to want to learn, change, and grow. It's the pinnacle of emotional immaturity for him to expect her to be attracted to him when he's acting closed off, complacent, and bitter. As you said, you feel vindicated when a guy takes "Let's just be friends" so poorly.
Most guys have no idea of what women actually are attracted to, so thank you so much for being honest and sharing it with the world! I think the issue in a relationship like the one I described is that the girl doesn't tell the guy: "You're no longer improving yourself and seem complacent." Instead the message is often "I'm not attracted to you" or "We need to break up."
The trick for a guy is that it's actually more attractive to a woman to him to change his patterns and look for new hobbies (particularly ones that he can include her in) than to stay with the same-old-same-old for years, no matter how successful he feels in his current routine. If he's someone who lifts 6 days a week, could he switch to 3 days a week and start a new hobby, athletic or not?
In the men's dating literature, Dr. Robert Glover is the expert here. Nice guys are unattractive to women because they have nothing underneath -- they only care what she wants. A "nice guy" hides his flaws and doesn't pursue his goals because he's "just another narcissistic superman living his own fiction" as you put it. Conversely, someone who treats women badly is sometimes seen as attractive at first because at least they're a real person with ambition -- even if they end up being a narcissistic jerk. The first few dates often seem mysterious and full of tension, all the more so when he's suddenly unavailable. If he's busy, he must be high-status, right? On some primitive level, I think that's the unconscious thought pattern.
Instead, someone who is genuinely attractive to women is someone capable of developing "Positive Emotional Tension" as Dr. Glover puts it. It's best understood by what it's not: negative emotional tension would be one or both partners nagging, complaining, being unavailable, withdrawing love, and otherwise causing drama. Positive emotional tension is when someone willing to open up about their vulnerabilities, weaknesses, flaws, ambitions, and more.
When a guy tells you "I'm not great at public speaking so I've signed up to a workshop" (as you suggested), that's positive emotional tension. That guy doesn't care what you think about his public speaking skills, and he's definitely not doing the workshop for you. Instead, he's trying to build a better life for himself, and he ultimately doesn't care whether or not you want to share in his great life. He's not someone who's going to take it personally if you tell him you didn't feel the spark, and that's sexy!
Dr. Glover has written a lot of great content on the subject, including a book https://www.amazon.com/Dating-Essentials-Men-Only-Guide-ebook/dp/B07RJ1JXNB and his course https://www.drglover.com/tpi-university/positive-emotional-tension.html ... I'd put your piece up there as an excellent resource for guys as well.
Ultimately, emotional tension is what drives female attraction, even if the "pick-up artist" community doesn't use the phrase. The "Mystery Method" (i.e. "negging" and freezing a woman out if she isn't interested in sex) creates negative tension. In contrast, the "Juggler Method" (aka "Charisma Arts") is simply about being a genuine person and learning to create positive emotional tension with women through conversational timing and vulnerability, exactly as you discussed.
I've developed close friendships from women who I went on a few dates with simply by being vulnerable and letting them know it wasn't working for me, instead of getting caught up in feeling that there was something wrong with me that we weren't clicking. It's great advice for all guys to take the outcome of "Let's just be friends" as not only possible but likely. Being at peace with that is a fast-track to emotional maturity.
For women, I'd say the corollary is that they'll be more men you want to date in the world the more honest women are with them. I have a close friend who refuses to tell someone she's not interested in him because she has some worry about how their mutual friends may perceive her. If "Let's just be friends" is too honest for her, then she'll never be able to help a man become more emotionally mature through real feedback.
A guy may not take it well (guys ghost too), but it's something I wish I heard a decade before: "I'm not attracted to you because you seem complacent, unhappy, and unmotivated to improve." At best, I got told "I'm not attracted to you" -- which sounds like it has to do with my physical appearance, instead of how I'm approaching my life. Thankfully, I've learned these lessons about dating by age 31, instead of later in life.
That said, women can do men a vast service with some honesty: "You're inauthentic, you only want to please me, you lack ambition, you're not self-aware, and you're not trying to improve yourself. Those are things I'm looking for in a partner, sorry." A guy who hears that from more than one ex-girlfriend is going to learn how to become more attractive to women, instead of becoming resentful about women.
Of course, there are very few women who would be brave enough to say such a thing. After all, she's not attracted to him, so why would she care if he goes on to become more attractive to other women in the future? I'd say the vast majority of people of all sexes are unfamiliar with these relationship dynamics, anyway. So we'll continue to see dates where the woman "mysteriously" isn't attracted, just as we'll see long-term relationships end for the same reason. Thanks for the great article!