This is not correct. Major R1 universities have grants and endowments as their primary source of income, but the vast majority of schools do not fall into this

This is not correct. Major R1 universities have grants and endowments as their primary source of income, but the vast majority of schools do not fall into this category. All liberal arts colleges, religious colleges, for-profit colleges, and most state colleges (i.e. non-R1 universities) desperately need tuition to pay the bills.