[iggldiggl]

> but it has the disadvantage that society has to really take care of not falling into demographic traps.

Does it? Or is it just that the demographic issues are more readily apparent?

You can't eat the stock market, so you can accumulate as much wealth as you want in stock market-backed pensions plans or otherwise – if by the time you want to retire there aren't enough working-age people left around willing to provide you goods and services, your pension scheme is worth zilch.