Most (if not all) gov't pensions still have the defined benefit part as the "optimal" choice even when they offer defined contribution plans.
They can also offer some really nice benefits like accessing your pension income at 55 which can be a substantial portion of your last year's salary, and you can keep working elsewhere if you want.
I have a close friend who absolutely would have taken a DC plan if it were offered, since he does not believe the city he works for will be able to meet its financial obligations. It was not offered. Granted I haven't talked retirement with him in about 10 years, so it's possible a DC plan is offered now.
I feel you have to watch your plans like a hawk, because as a pension crumbles there's often a window of opportunity where they offer to "buy you out" (basically turn your DB into a DC mid-stream) - and sometimes the deal should be taken.
Who do you think is buying .. everything? They're holding substantial fractions of both the whole stockmarket and national debt.