The guv'ment says different. It's not just income, but also assets. I get "expected family contribution" numbers that would put a serious dent in my retirement plans. Fortunately, merit aid is a thing where my kids go, and they get outside scholarships as well.
BTW, no 18yo with little income is buying a car from anyone...but their parents can, and income certainly does play into it unless you're a cash buyer.