Why did religious leaders guide Jewish society after the Jews return from exile?

Religious leaders continued to guide Jewish society after the Jews returned from the exile for one reason: they couldn't have a king instead they had a rabbi. Rabbis serve the Jewish community. Some rabbis program and guide activities designed to reach Jews who are unaffiliated with Judaism or lapsed in their observances.

Moreover, taking into consideration the importance of religion and its impact on Jewish community, it is no wonder that religious leaders are the ones who guide the people.