Define;
Is the daf purely an agudah thing ? Is the event about the daf or agudah?
I never thought about that question.
But now that you ask, as per Wikipedia,
The novel idea of Jews in all parts of the world studying the same daf each day, with the goal of completing the entire Talmud, was first proposed in a World Agudath Israel publication in December 1920 (Kislev 5681) Digleinu, the voice of Zeirei Agudath Israel,[7] by Rabbi Moshe Menachem Mendel Spivak[8][9], and was put forth at the First World Congress of Agudath Israel which took place in Vienna starting from Elul 3, 5683 / August 15, 1923 and which lasted for ten days.[10] The proposal for the study of Daf Hayomi was made on Elul 7 or 9, 5683 (August 19 or 21, 1923)[11] by Rabbi Meir Shapiro, then Rav of Sanok, Poland, and future rosh yeshiva of Yeshivas Chachmei Lublin and the resolution was adopted on Elul 10, 5683.So, while nobody has any rights to Limud Hatorah, it does make sense that they would spearhead it.