Why didn't Jews start making clever observations about the biblical text until after the Macabees?

Our friend Barak has pointed out that every book about Torah that we posses dates to mid-second Temple or later. We have no aggadic or halachic writings from before the Maccabees. Well, why not?

Have we lost and forgotten everything wise men thought and said about the Torah during the first Temple? And if it never existed, why not? Why didn't Jews start making clever observations about the biblical text until after the Maccabees? What changed?

[The traditional answer, of course, is that the aggadic and halachic writings known to us now were also known and studied pre-Macabees, and passed on from teacher and student, until such time as various Rabbis, in their wisdom, decided to reduce them to writing. This proposal reduces Chazal and their successor Sages to little more than stenographers, yet remains well loved in fundamentalist quarters.]