We have structured our global financial system around young people paying taxes to pay for the costs of the retired generations. Population decline is a real problem we will soon be facing head on.
It’s not really the “global financial system”, tax-funded pensions are mostly a richer-country thing. In less developed places, young people often “pay” for the elderly without ever giving them a tax dollar, e.g. by staying put to care for an elderly relative instead of moving somewhere with better pay or quality of life.
History is the process of oil getting into everything. The financial system is a structure for distributing surplus energy founded on growth resulting from accessing a material which can do 500 people's worth of work in a single barrel.
Well structuring the global financial system is one thing, but we really need assume very little about finance. If someone is retired they aren't working, so almost by definition others still working must provide for them.
No, this is not the case at the moment. The previous generation HAS paid lots of taxes, social insurance and retirement in order to pay for themselves. So let's not make up fantasies here.
Now will this be true going forward? Not sure, that's where you can argue.
It's not taxes that's the problem, you can't magically solve the problem by storing cash or gold under your bed.
If you increase demand for labour (more people getting old needing more care, more doctors) and reduce supply for labour (fewer people working), then the cost of labour will skyrocket.
Put 5 billionaires on an island and 1 carer. How much will the carer charge to care for an hour. They auction their time, and the bidding starts at £1m an hour.
As you’ve just said, the decline isn’t the problem, it’s the global financial system. We should be looking to reform that, not to boost the population: that’s a long-term impossibility in a closed system.