I see a lot of people in other posts, recently and over the years, asking how anyone can expect growth to happen with a shrinking population.
Investment growth is not population growth. It helps, sometimes a lot, but they are not the same. Investment growth is not profit growth either, but at least its a better estimate than population. Some examples:
* You can have growth with shrinking populations and less raw materials simply by being more efficient. Making the same number of products with 10% less material is 10% growth.
* You can have growth with less products being made by being more efficient, including paying less or automating jobs. If you make 10% fewer products but you do it with 20% less inputs, thats 10% growth.
* You can have growth if your own economy is in the garbage by selling to others who arent. If your businesses sell 20% at home and 80% abroad, then you can have growth even if the 20% shrinks to 15% as long as the 80% goes to 86%
* You can have growth even if all current products are fully saturated. Today's iphone adds nothing in terms of products vs a 2005 flip phone plus camera plus notepad plus calendar plus gaming handheld, etc. Theres nothing fundamentally added but by packaging the same products better you can have growth.
* Even if you have magically provided everyone with magically ideal products that meet all needs ideally, the market will just shift to new kinds of art and entertainment and those companies will grow as they invent popular art and entertainment.
* War can drive growth if it happens elsewhere. Your companies might change nothing at all but if your neighboring country needs to rebuild they will buy your stuff to replace what is destroyed and you can have growth even of neither country has a growing population.
* You can even get growth without your economy being any good. If everyone elses economy is worse, (say their currency and regulatory systems are considered weaker) then investment comes to you and you get growth.
TLDR population is only one of a dozen ways to get investment growth