Student loans by themselves are an example of a business anti-pattern in my opinion. Schools and governments should figure out funding models that do not charge the students huge sums of money because it's perfectly possible to organize an education system without that (as many countries demonstrate). It is immoral to drive students into debt.
Or, if you want a more rational reasoning: nowadays higher education is essential to gain access to knowledge worker jobs which are becoming the foundation of the post-industrial economy. Nations should want the best quality of students in those jobs, not just those who can afford the entry ticket. Therefore it makes sense from an economic perspective to amortize the cost of entry (higher education) across the entire taxpayer base and leave education as a purely merit-driven system where the best students get the most economically significant jobs.
Or, if you want a more rational reasoning: nowadays higher education is essential to gain access to knowledge worker jobs which are becoming the foundation of the post-industrial economy. Nations should want the best quality of students in those jobs, not just those who can afford the entry ticket. Therefore it makes sense from an economic perspective to amortize the cost of entry (higher education) across the entire taxpayer base and leave education as a purely merit-driven system where the best students get the most economically significant jobs.