Of course. I'm not talking about a girl making a guy wait for "date after date." I'm saying that if a girl gives it up to you within the first two dates, she's probably just using you for sex. If it takes a little while longer than that, then she probably likes you. Of course, you have to at least marginally understand the difference between being friendzoned and getting used and a girl who is into you.
A good indicator, I think, is whether or not her tongue is in your mouth. Just because she's not having sex with you doesn't mean that other sexual things aren't happening.
You are using logic to describe women. What you said makes logicaly sense....and that is exactly why it's not true.
You have a whole load of beliefs there that are damaging...For example, "sex is a commodity women trade for attention." That's pure horsesh1t. Sex is an extension of a woman's emotions....a way for her to experience men. Most sane women view sex in an emotional state. A way for her to experience emotions and feelings, receive validation, and develop intimacy. The women who don't view sex in that manner, are usually the sluts.
And it's interesting about your 3 date rule. The assumption behind that is that you aren't getting anything out of it unless you are having sex with her. It also assumes that you, the man, are giving your resources without getting other things (besides sex) in return. If you are doing these things, regardless of whether you are having sex or not, you are still embracing chump behavior.
Also, entering a date with that frame (that if she doesn't give it up quickly) is going to put you in the wrong frame. It's going to add unnecessary pressure to your interactions.
I attribute this general attitude around here to the swing of the pendullum. The men who come here have been walked on by girls for so long, that, when they DO change, they overcompensate...overshoot and move from being the "nice guy" into complete and total meatheads. If you're open to learning, though, the pendullum will swing back and you'll recognize that you can set boundaries (and hold those boundaries) without having damaging beliefs like the ones you are perpetuating.
Then you can recognize and understand women...and realize that there are other IOIs besides the common ones perpetuated in PUA. You'll release control of the outcome and stop trying to figure them out (they really aren't that complicated). And the moment you STOP trying to figure them out, you'll realize that you've figured them out. You'll stop holding ridiculous goals (such as sex on or before the 3rd date), you'll set realistic boundaries (as in, if the relationship isn't escalating in a sexual manner, you know that you'll eventually walk), and you'll stop labelling women as "HBs". There will be "Yes, she's hot" and "No thanks." You won't feel a need to rate women, you won't feel compelled to get sex from her right away, but you'll know when you are being duped. You'll be strong enough to walk away from a situation that you aren't getting something from. And, finally, you'll realize that there are more ways to escalate beyond just sex, that foreplay happens from the moment you say hello (and not the moment you feel her up), and that you have something to offer her (does she have something to offer YOU?).
Now I'm just rambling (and I threw in some extra stuff based on the attitudes I see on these forums). Mostly, I think a lot of "clue" getting needs to happen here. I don't pretend to be a guru on women, but I've figured out that much at least. And it works for me.