Let me define a billion dollars. Suppose you had to physically move one billion dollar bills to the bank. A one dollar bill weighs 1.02 grams. At this weight, it would take 445 one dollar bills to equal one pound. While I know of no chiropractic college that retains a billion dollar endowment, I believe each one would benefit from having an endowment of any size.
Some schools plow unspent tuition revenue at year's end into an endowment fund.
Such action may seem unfair to the current students, but it helps to ensure the long term viability of the institution. The most obvious source of endowment funding is through gifts and donations. With varying degrees of effectiveness, every college president has asked someone to make a donation to their respective school. Most colleges support a fundraising or development office on campus. Through that office, a variety of fundraising efforts are launched.