Didn't the pension funds all go broke because the regulators let them undercapitalize them to start with on the assumption they could make it up in the market,

Didn't the pension funds all go broke because the regulators let them undercapitalize them to start with on the assumption they could make it up in the market, and then whenever markets went down and they would bust? I mean, I agree that it was a tragedy, but ISTM the blame goes to the people in the 60s and 70s who were like "Oh yeah, we don't need to pre-fund the pensions. GM will live forever, and the market will never go down."