DA asked:

"why is it we never confront the underlying issue when discussing them?"

You already answered your question:

"The concept that reproduction is good for the economy is the argument of the retailer."

Canuck wrote:

"More people equals more minds equals more human horsepower available to solve problems."

Unfortuanately the next time human population numbers in the world crashes it will not be the first time. Populations have certainly completely died out at times regionally, usually through over-exploitation of local resources. This is another issue that is not confronted often.