Is there any way government pension systems can be reformed to in a way they are proofed against changes in the ratio of economically active and dependent people?
I think a very basic exmination from first principles of the problem of any pension system can answer that.
When someone receives a pension, that means they receive labour but don't provide labour. No matter what you do and how you finance the pension, this can't be changed. You can not "save up" labour and get it back later. You can try to take measures to reduce the labour the retired people will need, but this is no substitute for a pension system that can cope with different ratios of working people versus retired people living of others work. Ways to reduce the amount of labour needed:
- Improve economic productivity. Yes, well... we are trying to do that already. It's sure to help, but either it will keep up with demographic changes, or more likely it won't and there is nothing we can do about that considering it's already a prime imperative of any capitalistic economic actor to try to be as productive as possible.
- Save up things that save labour later, be it finished goods retired people might need or things that take labour to make and the retired people could exchange for things they need. But that's just here to name all the possibilities that come to mind, hoarding things is bad for the economy and is just plain impractical.
- Saving up money won't change anything about the equation of how much work needs to be done versus how much work can be done by the working people.
So when the ratio of working to retired people changes, the working people will need to provide for more non-working people with their work if you want to keep everything else equal. You could of course try to keep the fraction of all labour that is done for retired people constant, but most of the possible measures are either not practical at scale or not desirable:
- Get more working people:
- Immigration (problems at scale, plus ideological opposition by some groups).
- Incentivising having children (easier said than done).
- Raising retirement age
- Reduce the standard of living post-retirement
To get the working people to provide for the retired people, there are basically two systems:
- Pension from investments (where some people like to forget that the working people are still providing for the retired people)
- Distributing tax money to retired people (where it's obvious that the working people are providing for the retired people)
Both systems can easily be adjusted for different demographic compositions or anticipated changes as follows:
Pension from investments: People "save" for retirement individually. From the point of view of the whole population, this means that retired people hold a significant fraction of the total capital in your economy and capital ownership is skewed towards older people in general. In a sense this can be proofed against demographic changes by choosing (or legally mandating) which fraction of working people's income needs to go towards buying pension investments based on anticipated demographic (and other economic) changes. It's not possible to guarantee a specific level of comfort/income with this system, because you need to set the amount you pay in during your working life and once you are retired, either you have enough or you don't. If a lot of people didn't pay in enough in this system, the difference will be made up by the distributing tax money as in the other system (with the difference that people will be happier to receive a pension than welfare handouts).
Distributing tax money: Here it's clear that nothing is really saved up, but that the pensions are provided by working people (as in the first system too). Tax income (of working people) is distributed to people who are entitled to a pension. There are different ways to determine how much payouts a retiree is entitled to. Most people would agree the payout should depend on how much someone worked/paid in tax. Most people would probably agree there should be a minimum payout, because otherwise the state will have to provide welfare payments anyway. Based on those two assumptions it's easy to work out a system independent of the ratio of working to non-working population. You will have a function of lifetime tax paid to pension amount. The function could be such that someone who paid twice the tax also gets twice the pension. At the lower end, you will have to cushion the function so poor people can still survive. If you want, you can also do something about the high end, for example reducing the growth of the pension to below-linear with respect to tax payments. Some existing pension systems even have a hard cap at the high end. And then you just determine each year the amount of tax you need to collect and change the rates accordingly. You could also add a feature that someone could pay in more voluntarily in exchange for higher pensions which would make it a little more difficult to set the mandatory rates correctly, but still easy enough.
Either way, working people still do the work for the non-working people.