And in some years it grows less, or even shrinks. The whole point of an endowment is that it is supposed to support the things that it was funded to support in

And in some years it grows less, or even shrinks. The whole point of an endowment is that it is supposed to support the things that it was funded to support indefinitely. Most endowments, including Harvard's, already spend each year about as much as is they reasonably can while not putting its long term viability at risk. Also, endowments are not one big pool that can spend on whatever the university happens to want. They are comprised of thousands of separate pools created by donations that were donated on the condition they be used for specific things. E.g., some rich person leaves a bunch of money to a school to create the Milburn Pennybags Professorship of Antitrust. That money goes into its own pool in the endowment and its earnings will legally be restricted to funding that one professorship.