Some people don't qualify for enough aid to cover their expenses, and cannot pay the difference themselves, even with work. Loans are a risk these days.
Some people get enough aid to cover basic school expenses (tuition, fees, maybe room & board), but still struggle to pay for textbooks, toiletries, and other expenses. Students who don't live on campus (which is very expensive) might struggle with food, transportation, and utility costs.
Some people are lazy, sure. Some people aren't prepared for college and should pursue other options. But some people face significant financial barriers to attending college.