One possible solution is to have education financed by equity rather than loans, the third party who pays for your education does so in return for some share of future income. Besides the obvious effect of funding profitable education, this has the totally awesome side-effect of giving great incentive to an organization to figure out exactly how much each person's income will be increased by each job - which includes predicting salary, probability of graduating, future macro trends, etc.

The third party wouldn't have much incentive to predict what jobs will be most fun (only whether you will hate it so much you quit), but at least a big chunk of the problem would be solved. Personally I think the solution would involve "higher education is rarely worth it", and direct people towards vocational training or just getting a damn job. But I could be wrong - the great thing about a mechanism is that I don't have to be right about the results to know that it would make things more efficient :).