Motivation in Newton's career.
In his early career Newton was disinterested in publications. In a letter in which he solved some problems of annuities he wrote to the recipient:
This suggests that Newton was driven at least partially by curiosity, although the aspect of "public esteem" comes into the equation as well. He certainly did increase his acquaintances after he was elected member of Parliament for Cambridge University and exploited his new contacts. He is reported to have complained that John Locke, who he had approached for help, "would not care to visit such an unsuccessful place-hunter as himself, and if the Monmouths now forsook him, there would be no hope left; and he must reconcile himself to end his days in the obscurity of an academic life."
Crowther, J. C. (1967) The Social Relations of Science, revised edition. The Cresset Press, London.