So there's 25,000 people that applied and 4,000 accepted. That means that less than 1/6th that applied were accepted. I would say that most that applied were serious about programming something (I mean, its pretty expensive). So that leaves ~20,000 people that have something but are not accepted. There are also going to be cases (like me) where the developer needs to test on a real iPhone (for various hardware and software reasons), but cannot, so are waiting until they are accepted so that they can develop further.