[ghaff]

Nothing is keeping you from putting some portion of your salary into long-term low-risk bonds or even into annuities of various types. Your total compensation is presumably the same (given tax effects) so you're basically saying that you'd rather an employer handle some portion of your savings for you than handling it yourself. And there have certainly been defined-benefit failures and reductions of various kinds so there were pretty much never any guarantees.

Again, you seem to be assuming that there was some special pool of money that went into defined benefits that got pulled back. Which isn't true. Companies pay what they need to hire including benefits packages.