Why is it that when rishonim quote from the Talmud Yerushalmi they don't quote the daf?
Nowadays, the Talmud Bavli normally uses the printed edition of the Vilna Shas. Those who write translations or extra commentaries, will use the Vilna Shas pagination in order to keep the references standard. Those commentaries or references that came before the Vilna shas was printed can only point to the perek and mishna within the perek because the pagination had not yet been standardized. The Talmud Yerushalmi did not have a standard printed edition to refer to.