A graphic that goes along with a Wall Street Journal article on Harvard's budget divides Harvard's revenues up between "current-use gifts" and "endowed gifts." The graphic defines "current-use gifts" as "generally cash donations that can be spent down in entirety; for instance $100,000 to endow a named faculty chair, or graduate student travel and research."
Maybe prices have gone down, but last I checked endowing a named faculty chair at Harvard cost way more than $100,000, and Massachusetts law restricts spending down anything called an endowment.