I've yet to hear of a job where the employer strictly follows their own "requirements." Most simply post it as a "perfect candidate" guideline and end up settling for someone meeting 75% of it, so don't take them too seriously.
Yep. If you're an employer, why would you advertise that you're actually looking for that 75% candidate? You'd get all the trash candidates (probably getting them anyway) and the good candidates would be like "Ew, I don't want to work for that company!" HR-types are often the ones to write those requirements, anyway, and they're just reading Internet tutorials on how to do so.
I've been there (as an employer), and because my boss often made it very difficult for me to hire when I needed to (always based on current billing instead of future billing), I had to be very particular because I knew that if I chose poorly, I wouldn't get another chance for quite a while. I interviewed many good candidates, but often opted to not hire and keep waiting for the reasons mentioned above.