The equation is how much hishtadlus is necessary vs bitachon, (assuming that you believe that g-d is the provider).
In the yeshivish circles the common hashkafa is that its not necessary to waste the most productive "growing" years for the concern of having a relatively secure source of parnassah in the future.
Therefore most do not go to 7 year collages.
The facts are that a vast majority manage without the whole education thing when it comes time to make a buck, some get a fast degree later after marriage etc.
[Im not even discussing the danger of the current college culture and the poisonous views that many courses teach]