Avram, re:educational system. Note that Bava Basra directly relates to the age of schooling. At least one of the methods tried during that period was to start at teen ages (and the result was that they did not listen to parents). So, they were not following Pirkei Avot. Maybe not surprising – avot misha is either by Yehuda b’ Tema or Shmuel HaKatan, both late tannaim who seemingly lived after the school experiments.
I accept a possibility, as you say, that avot advice may be normative and BM2 period was an exceptional period. But so are other periods, especially current one. Modernity uprooted so much and created so many opportunities – including our capability to measure results. So, I would say Bava Basra experimental approach is so relevant.
Also, Ketubot 50 discusses ages and seems to suggest that 6 and then 10 or even 12 are _earliest_ ages to teach, that is, one should not force a younger kid. This is discussed in Usha, so it is post-BM2 when things got even worse …