Abū al-Rayḥān Muḥammad ibn Aḥmad al-Bīrūnī was one of the great figures of the golden age of Islamic scholarship, and deserves to be more famous in the West than he is. As an expert on many subjects in addition to mathematics, he knew a lot about the uncomfortable relationship between professional thinkers and the people who pay them — as this quotation attributed to him illustrates.
Once a sage was asked why scholars always flock to the doors of the rich, whilst the rich are not inclined to call at the doors of scholars. “The scholars”, he answered, “are well aware of the use of money, but the rich are ignorant of the nobility of science”.
(In A. L. Mackay, The Harvest of a Quiet Eye, IOP Publishing, 1977).
Some things never change…