>a lot of our economics presumes growth and, if we don’t get it, a lot of terrible stuff happens

What does this actually mean? Every time I try to wrap my head around why it's bad e.g. for a business to make a constant profit, rather than an increasing profit; or for the population to dip to some number and settle there, rather than increase; the explanations seem to become circular very quickly. I know it's partially my fault for not having a very strong economic education, but it also feels like something is fundamentally wrong with the theories - like they are making some underlying assumption about what is "good" that I don't share. But I can never seem to get down to it.

The only thing I understand is that as the ratio of old to young grows, more taxes are needed, of course. But that would only be painful during a significant rate of change, not after the number is stable, no? Is that really somehow apocalyptic?

> more taxes are needed

Don't forget it's not just taxes, but the allocation of labor and resources. If the entire population magically turned 90 tomorrow, no amount of taxes would be able to provide for them.

There's no reason to think things would stabilize but even if things roughly stabilize in terms of population there's problems.

When a certain region in a country gets a cluster of great companies or really any productive advantage you would want more buildings and people there. In a country with a growing population that would make most sense as you need to build houses regardless as there's more people entering the job market who need a home. In a country with a stagnant population for every home you build another needs to be abandoned. This is more expensive especially when this happens enough where a school in the 'abandoned town' closes and a new school should be made in the better town. You can see how the first is more efficient, you don't waste your fine buildings.

Here is what it actually means.

When the economy is growing, investment makes sense. Why put your money under the mattress when it could be out there, working for you?

When the reverse happens, investment stops making sense. Why risk your money when it becomes worth more while it is sitting under your mattress?

But stopping investment does not just mean stopping speculative investment. It means stopping investment in other things as well. Like maintenance. This guarantees that things are going to become worse over time. Which is a feedback loop that makes investment even less worthwhile.

This has happened in the USA before. The last time is called the Great Depression. Read through accounts of what it was like. Would you like to go through that now?

History also teaches that the longer it is between economic setbacks, the worse the next one tends to be. We've gone far longer since a depression than at any point in history. Our next one is likely to be correspondingly more terrible.

Honestly great question. I think of it as:

I invest my wages to take advantage of compound interest. It’s kind of my only hope of having a family / owning a home / retiring. If stuff stops compounding, I’m fucked. Multiply by however many millions of people are on the same position.

I don’t necessarily think the theories are making any assumption about what is good (except for the “greed is good dicks”)but more acknowledging that this is how our system currently works and the first generation to step off this ride will have a horrible time.