Why were previous generations not punished for their sins?
Malbim: They totally forgot the Torah, and did not know it at all 1 . All they did was due to this. They were like a baby captured via (and raised among) Nochrim, who knows nothing of his father's Torah. All his actions are one Shegagah.
How could Torah be forgotten in a short time? Youths learned Torah, and they would live another 50 years or so, and if they wanted to serve Hashem, they would teach their sons! Perhaps Malbim means that evil kings stopped people from learning, so the people were totally Shogeg. (PF)
What is the meaning of "Osi Azavu v'Es Torasi Lo Shamaru"?
Malbim: They did not guard Torah at all, and since they did not know Torah, they abandoned Hashem and served idolatry.
