Why project managers who take the certification course don’t take the PMP exam

I have been teaching the PMP Certification course for 7 years and have taught almost 500 students. Only 42% take the exam. For those that take the exam the pass rate is over 94%, but why don’t the rest take the exam?  Here is what I have discovered and speculated. First, there are some who may have taken it and not reported that they passed or probably failed. That percentage is probably less than 3%. Most don’t take it because of what I call Life Happens. All those other things in our lives get in the way of a task that isn’t a favorite thing to do.  The longer after the class that goes by, the less chance of taking the exam. After 3 months that drops to only 10%. Face it; no one wants to take a 200-question test. There is peer pressure, job pressure, and a fear of failure in general. Another big issue with the exam is the application process which can be difficult and requires a good bit of work. The last reason is the required preparation, reading and practice questions needed for a successful exam result.  Taking a prep course takes 35 hours of your time over several days so why not go ahead and also commit to take the exam. Perhaps paying for the exam as part of the course might help make the test takers more committed. I’d love to hear your comments.