Every girl wants a guy that will open doors for them, pull out their seat, stand when they are leaving the room, but this is hard to find these days. During the Middle Ages, this code of conduct would be expected of every man, so where has this quality of a gentleman gone? It hasn't disappeared, but it's about as scarce as an endangered species. It has evolved so much that it would be almost unrecognizable if not for its classic touches.
You see, the idea behind the Middle Ages chivalry was basically the same as the dating game in the 21st century- try to win the girl. The whole concept starts when this guy likes this girl and wants to get to know her better and possibly make her his own. So he makes his plan, and begins to flirt with the girl, what they would have called "courting" in the Middle Ages. He would try his best to win this girl's affections by doing things that he thinks the girl would expect or want from him. This basically will lead up to the girl's decision to keep him or lose him.
However, it is the flirting/courting that has changed so much. During the passing of each generation, the generation before doesn't want to do the same thing as their elders have done because its considered to be out of date or unimportant. So eventually, acts of chivalry have been removed from most men's code of behavior. Unfortunately, when removed, these guys did not bother to replace the absence with a new display of affection. As time passed, many more of these actions were forgotten by most, remembered by few. This explains how chivalry is almost nonexistent.
Another explanation of chivalry's low profile presence would be the new attitude of today's women. We want to be independent, in control, and not taken care of by a man. Women want to show the world that we can do this on our own and we don't need some guy to hold our hand along the way. You see, the male used to play the major role in relationships, especially during the Middle Ages.