Yup, the influences on e.g. Newton happening to delve into reading up on Archimedes, Descartes, Fermat, and then synthesizing their inventions in his mind with lot of time on his hand, or for that matter Leibniz getting math tutoring from Christiaan Huygens seem to be crucial in relation to the invention of fluxions/infinitesimals. (Approximately from memory of reading Infinite Powers by Steven Strogatz).
Doesn't diminish their achievement in my mind.