No business would be run like this, you fund your pensions over 30 years, not 10. The USPS is failing right now simply because that's what the republicans want, it's purely political. The tea partiers are having their to at destroying the economy.
Most libertarians dont get economics very well, they just think taxes and government are evil. Capital is not something you can save in a silo or go negative. It just flows to where it's most needed at any given time; you see it has to be spent, saving fiat currency is just a way of moving it (if you save, someone ELSE must go into debt at the same time).
Now what does economy of our kids look like? It solely depends on what they produce and consume! But that also depends on how we spent the money in the past invest in the future. Education, infrastructure, R&D, ... Didn't invest? Well your kids will suffer. Oh, china had money burning a whole in its pocket and you decided to let them inflate rather than take the money at a negative interest rate? WTF are you an idiot?
Now what are pensions? They are simply investments for the future! But you have to pace those investments and time them just right, so you don't kill yourself now and can meet obligations in the future.
The real problem that will hit us in the ass: most of us aren't covered by pensions at all and we are finding out that 401k's aren't a great alternative. That will be a bigger burden for your kids (assuming they don't abondon you) than any kind of debt they have to pay off for us (really, they are probably just paying you anyways).