Jewish law is justificatory, often revealing its own raison d’être, Apodictic Mishnah, on the other hand, constitutes a deviation from this overall trend of vindicatory law. It runs counter to Jewish apperception, which favors laws that justify themselves, either logically or scripturally. No wonder Mishnaic form was relatively short-lived, lasting only about 130 years. Mishnaic form initially emerged as a response to the particular political and religious conditions that prevailed in Palestine during the period following the destruction of the Temple. During the second century, it was supported and upheld by the Patriarchate, particularly by R. Judah Hanassi. After his death (ca. 220-221), Mishnaic form was gradually abandoned, and the Jewish apperception for justificatory law prevailed.
David Weiss Halivni, Midrash, Mishnah, and Gemara: The Jewish Predilection for Justified Law (Cambridge, MA & London, UK: Harvard University Press, 1986), 4.