We do still actually see that lower income households tend to have the highest birth rates, even in places where child labor is outlawed.
And I’m gonna disagree about the demand thing. People have demands from the base act of existing. Lower income people have proportionally higher demands. Their entire income is consumed and goes to other people. If you’re looking for people to do economic activity and whatever tasks you need done by a human, low income people are usually incapable of seeking a life elsewhere, and quickly return any compensation they get to circulation near where they are.
Lower income households also have the highest mortality rates and shorter lifespan.
I´d argue higher income people spend money a lot more money on other things than the basics, like apparel, entertainment, travel, starbucks coffee, … Entire industries disappear when people can´t afford the products or services. In times of crisis, people stop certain spending and you get all the restaurants, hotels, amusement parks, fancy shops and so on crying they don´t get as much business anymore and slowly start to go bust.
