No, it's about the scale of society and how we support ourselves in retirement, though. See, if retirement funds rely on, as the guy above me says 1. Companies underpaying their employees and 2. Governments taxing a group of more people in the below generations than there are to support in the top - then those are unsustainable sources of retirement comfort.

So what would be sustainable? Well historically, and in some countries today, old people need family to support them into old age. You would need either your own kid, with their own house big enough for you, or a rich little nephew with a house big enough for all you and your siblings to live in while retired.

Or... We just do the decent thing and take care of non-relatives. To ease the load on, say, retirement homes, we'd need to agree across society to bring the old people into communities of younger adults, and those younger adults would need to check on them regularly.

Sice this requires a community binding together, you might call it "communism." Though it isn't necessarily Marxism.

Why do you care about the ratio of workers to old people? What matters is the ratio of dependents to workers. We have more retirees, but we also have fewer children. This isn't that hard. If we could manage the Baby Boom of the 50s, we can manage this.

How do nursing homes do it?

Actually it is a communism vs capitalism thing. The problem arises in both, but the solutions available depend on the system. I reccomend you look up how China is handling its massive elderly population. For example the elderly there have huge public parks and get outside moving and socializing a lot. In big cities it's common for them to have mid day slow dance meetings in the parks. This is only possible because the government's priority is not producing profit for billionaires but caring for its people. So it maintains these things and the public transport required to get the elderly there, and the assistance to keep them fed and healthy.

This video is 15 years old: https://youtu.be/SvmV7GRRPq0

When people stay active and a part of their community into their old age instead of sitting in their huge houses alone or in a nursing home they require much less support to keep living.

Immigration!

Oh...