Politics wasn't fundamental to most people in identity sense for most of humanity's history, for the simple reason that most of them didn't have any political power to speak of, even notionally. Which, to be fair, is still true - but we've got better at pretending otherwise.
It's striking to me how all my friends in the USA talk about politics nonstop, but now that I moved to Japan practically nobody under the age of 40 seems to care.