Earlier quoted context omitted.
You could increase the taxes on pensions to return them to sane levels.
I feel wary of doing this because I feel this is what's going to happen with my IRAs. I was promised that if I pay my taxes now I don't have to pay them when I'm old, but supposed the next generation decides they want to change the rules. Do I just pound sand and give up? Pensioners were given a promise and now we're changing the rules. It feels wrong even if the promise was unrealistic.
There is a slight difference between the two situations you describe. That being that the promises being made to the unions were not being done by disinterested parties. Public services unions are notorious for being some of the largest donors to state and local candidates. The negotiators on the management side of the table are deeply beholden to the unions and have no personal interest in paying the obligations they are agreeing to, it's all put on the tax payer.