At any point in time, people can only consume what is produced or drawn from inventory. Old people, if not working, can only benefit from services only to the extent that someone is working to provide them.

In that respect, whether it's redistribution or capitalisation doesn't change a thing, only the way the overall pile is shared between those who work and those who don't

The only thing that introduces a change here is if you can call on "work" from elsewhere. The argument for market based pensions is that they can invest in more dynamic countries elsewhere and thus 'import" the wealth back home instead of only relying on the locals' work. But the same is true of a country which has finances sound enough to be able to buy imports directly.

Wind power