A defined-benefit pension is a math product. The same product could theoretically be sold as an individual account. You're X years old? Statistically likely

A defined-benefit pension is a math product. The same product could theoretically be sold as an individual account. You're X years old? Statistically likely to retire at Y and live to Z? If we assume N% average rate of return, this is how much you have to pay every month until then to get a given payout at retirement. The risk theoretically belongs to the issuer, who has to eat the difference if they underestimated any of these numbers, and their reward comes from pricing conservatively and keeping gains beyond the promised return. What has gone wrong were yeas of assumptions that weren't just inaccurate, but consistently inaccurate in over-optimistic directions. "We'll average 16% per year when 7 is more realistic." "Everyone will drop dead within 36 months of retirement." and seemingly "Nobody will plunder or slash contribution that were negotiated long ago."