Isn't this confusing cause and effect? Fewer people are having children because it is harder than ever to afford a family, not because the locals have decided p

Isn't this confusing cause and effect? Fewer people are having children because it is harder than ever to afford a family, not because the locals have decided passively not to continue on. Immigration absolutely depresses wages - if you import more supply, what happens to the price? That doesn't require advanced economics to understand.