And just in case you wanted data rather than anecdote:
https://ourworldindata.org/grapher/children-per-woman-fertil...
Your world view is somewhat upside down!
economic _hope_ is at its worst in the entire history of the human civilization. At what point did the future for the average person, look so bleak? And
that hope is what dictactes wether people have children.
Even during the great depression, people were more hopeful that the earth isnt completely hosed.
Does anyone honestly feel like _any_ improvements are possible to: our economic systems, political systems, environment? I certainly dont.
We are in fact in a better place than we were then. But we don't trust the derivative.
Economic output has increased, but the value being delivered to the people doing the actual work has decreased. There's less durability of employment. People are more geographically mobile.
All of these generally make the idea of strapping yourself into taking care of a small human sound like a less enticing prospect. To a lot of people, a BC pill sounds a lot easier. Well, less risky, at least.
People who live in huts and shit in the forest have more children than people who live in shacks and shit in the fields.
This is not a discussion about the top 10% of the population of the planet, although as a part of the conversation, they predictably have the fewest children. The fact is that the more people have to worry about supporting themselves, the higher infant mortality, the closer they live to each other, and the less access they have to education and birth control, the more kids they have.
If anything the top 10% are bucking the trend by having fewer children as they get poorer, as you say. It probably has a lot to do with the fact that they're alienated from their families and live alone, can barely afford to take care of themselves with precarious jobs (or non-job piecework), have access to basic education and extensive birth control, having children will cost them $20K each just for the birth, and they don't have very good (or often any) insurance. They're more like domesticated farm animals than the typical poverty stricken person. Domesticated farm animals reproduce when the farmer wants them to.
All poor people everywhere have more kids even today.
Actually, the famous 'Mouse Utopia' experiment (Universe 25) arguably showed the exact opposite. The population collapsed despite abundance of food and water without any economic hardship.