[KirinDave]

In the interest of historical accuracy, Newton's work was directly and indirectly subsidized by his government as was the university he attended (that later gave him partial scholarship). He invented Calculus while isolated due to the plague, but had already graduated by then with those scholarship bucks from a university chartered by the British government.

A lot of his work occurred while he was what we'd now call a tenured professor of mathematics, again at a universe with an impressive amount of money being donated directly by the British government.

In general, the history of higher learning is the history of governments (or the wealthy people who constitute them) funding research and facilities. You may not like it, but you shouldn't misrepresent history just to make your preferences sound more normal.

[WorldMaker]

There's also that the Royal Society [0] sponsored some of Newton's work (and Newton was even President of it for a time). That was a group also chartered by the British government (and some centuries financed by it more than other centuries).

(Leibniz had a more complex web of patrons over the course of the decades, including parts of German and French governments and even briefly being a Royal Society fellow. Some of Leibniz's patrons did include private [rich] donors, but it is said that Leibniz was the last scientist/mathematician to find patronage in that way/the last time in history that private donors had shown much interest in direct science/math patronage.)

[0] https://en.wikipedia.org/wiki/Royal_Society