Let us start off by observing a simple fact. If we ignore the relatively small group of people who are either physically or by character particularly ugly, we can make a very accurate statement, which is as follows. Any woman in a bar doesn't need to go home alone if she doesn't want to; most any man, most of the time, will have no other choice but than to go home alone.
Perhaps you are a woman, and think that this is absurd. Sure, if you lowered your standards enough, you could go home with a man from any bar, but you're looking for a GOOD man, right? No, you're not; you're looking for somebody who will give you attention and affection and make you feel special. Now, sure, you have your preferences, but trust me, most men will be capable of giving you that. Okay, you may have to put up with a bit of his bullshit, but ultimately, you can get what you want.
Perhaps you're a man, and you're thinking, "come on, dude, I may not get lucky every time, but often I'm the one taking the ladies back to their place." Well, good for you then, friend. You're lucky enough to have something special, something noticable, something particularly attractive to at least some small subset of women. Maybe you happen to look like a currently popular actor, or you have a particular wit or skill that attracts women. Ride it while you can. Just understand that there are quite a number of us who -- for some reason or another -- are not quite so lucky.
We can be gentlemen, well dressed, polite, good at conversation, stable, well-educated, and so forth, and yet, for some reason, we don't ever get to be the one taking the girl home. And here is my hypothosis on why this is so.
Let's go back to the original statement about men and women leaving bars. It's probably fair to say that both men and women are looking for the same basic things. Maybe presented a bit differently, but ultimately the same. That's affection, attention, and some sort of compassion, support, or security. Women have the upper hand here. By men's nature, we are all to eager to show attention, affection, and so forth to ladies. They know -- if only subconsciously -- that they can get what they want from a lot of men, if not most men. Men, on the other hand, have to work to get it. We know women can go elsewhere.
Here's an example: Let's say a man and woman have just recently met and are doing something enjoyable together. Now, if it's a date, that's another case, but let's say they're just being social. What about the line, "I'm glad we could share this moment together." Coming from the man, and said to the woman, it's creepy. The man is intruding on the woman's personal emotional space. Coming from the woman, though, and said to the man, it is a totally different case. It may be a bit awkward, but only the fewest men would feel nearly as insulted as in the reverse case.
So what does this mean? This isn't exactly anything new.
Men offer attention and affection regardless of reciprocation. So most any woman knows she can get what she wants out of him without doing anything herself. The man, by his nature, will keep trying to entice her by showing what a nice guy he is. But he's already played his cards. Of course, should he have something special, then maybe the woman will reciprocate to keep him for herself, but most of us aren't that lucky. By being friendly to a woman, the man has already given her everything he can offer. She -- quite reasonably -- can save her trump cards for a man who can give her something special.