Well, that is true if you are talking about higher education, but people still need to learn some basic skills (writing, reading, counting, etc.). Learning English is often useful as well (note that before replying to your comment, I expected Libya to have a low rate of alphabetization, but it turns out their alphabetization rate is rather high (source: http://en.wikipedia.org/wiki/Libya#Education)).
On top of that, they probably need some skills in the fields of medicine, or petrol engineering.
They have the trade off between paying for that with oil money directly now, or being able to continue to pay for less of it, but being able to continue "forever" by investing the oil money, while the principal grows rapidly as long as their oil revenue keeps coming.
It's the age-old tradeoff between saving vs. immediate gratification.
On top of that, they probably need some skills in the fields of medicine, or petrol engineering.