Right, not entirely from current income. Maybe majority for most of people.
Let’s say student borrows a loan of 10K/year - same as most public colleges. Then savings and Education IRA and others contribute another 20K/year. Then the rest (40K/year) will be picked up by income. Still very significant life stye change. Also the savings will not grow for four years since the supposed money will be gone.
It is an individual case. Someone thinks it is worth the money and others do not think the same way. Both way is fine since private college education may not be the most important thing in life.