I feel that even though extrovert-introvert relationships probably work out better than extrovert-extrovert or introvert-introvert relationships, people are attracted to similar personality types. If you think about it, a guy that's extroverted and goes partying all the time would look at a girl that doesn't say too much and think that they wouldn't have that much in common.
It could also be that lack of communication between you and the guys that you're interested in makes them think that you're not interested in them. It could also be your body language too.
You need communication. Introverted vs. Extroverted doesn't necessarily mean that you can't find a quiet girl. It just means that you need to communicate better with her. Letting issues slide is the death of a relationship, unless you both have really and truly moved past them. Also it's probably hard for two quiet people to meet because they are both quiet. If you don't talk to a girl, and she is quiet... she probably isn't going to talk to you. It's that your personalities are preventing you from meeting.
If you go and talk to some girls it doesn't all of the sudden mean that you are 'conforming to today's popular culture.' Introverted doesn't mean 'no friends.'
(sorry for that aside to >>5, don't want to de-rail the thread)