Agreed. Endowments, to be fiduciary responsible, are adhering to the 4% rule. An endowed professorship, at $1 million, can spend 4%, or $40,000 per year, adjusting upward for inflation. Additional earnings add to the principal to compensate for the additional rate of inflation.

Spending more violates the rules for wise philanthropy. You risk running out of money, in the long run.