Because access to cheap student loans is key to many of us being able to afford college? Tuition and even room + board aside, there's other costs like books ($$

Because access to cheap student loans is key to many of us being able to afford college? Tuition and even room + board aside, there's other costs like books ($$$), supplies, transport etc. that cost money — money that many from poor backgrounds don't have. Without being able to borrow (or making it very expensive to do so), it would require a part-time job on top of a full coursework, or taking longer to get a degree, which has it's own costs associated with it via lost earnings.