"He's just not that into you"

I enjoyed the movie. I hated the f*cking book though. If you ever get your hands on it, I'll tell you right now that most of it spews negativity and shoots down any excuse we might have given ourselves for a guy's erratic behavior. To sum it up- hardly any guy is worth our attention and time, but what irks me the most is that it was partially written by a guy who pretty much tells us that:

• If the guy doesn't call when he says he will- he's just not that into you 
• If the guy doesnt call the next day- he's just not that into you
• If the guy says he's not looking for anything serious- he's just not that into you
• If the guy doesn't ask you out- he's.... well, you get the idea

So what if the guy doesn't want to get married? I find it completely acceptable for a guy to no want to legitimize a relationship- mainly for the proven fact that 50% of marriages end.... well, in the shitter. What's wrong with simply being committed to one another without having to make it legal? I'm on board!

If he doesn't call me when he said he would, I'm not going to dismiss the fact that he's not into me. 100% of the time I expect him to call me each time. Well... what happens if he's thinking the same thing about me in the very beginning, when he doesn't know how I feel about certain things? "She must not be into me if she's not calling....." and soon enough, it begins to faze out. I get very busy and sidetracked, so if he sends me a text and I can't respond right then and there- it doesn't mean I'm not thinking about him; it just means I'm extremely busy and can't get to it. Side note: If he doesn't text back until the following afternoon however, yeah, I can take a hint.

My main argument is that if we just give up at the first slip up, we're eliminating the chances of finding someone who's truly worth it. Can someone at least agree with this theory??