A topic that would require weeks to discuss properly and, since I largely agree with you, here is ONE thing I'm pretty sure should drive public policy:
So far, "paying people to have more kids" has always meant, in practice, "let's try to make ALMOST EVERY woman have ONE child, possibly TWO, by giving them some money" (and nothing else). And by now we already know it doesn't work, for all the reasons you already mention, and then some.
Considering this, it's probably much more effective to give a LOT of money and other assistance, but really a lot of both, to the minority of people who'd really want not 1 or 2 but 4, 5 or more kids. There still is enough of them in "First World" societies.
A topic that would require weeks to discuss properly and, since I largely agree with you, here is ONE thing I'm pretty sure should drive public policy:
So far, "paying people to have more kids" has always meant, in practice, "let's try to make ALMOST EVERY woman have ONE child, possibly TWO, by giving them some money" (and nothing else). And by now we already know it doesn't work, for all the reasons you already mention, and then some.
Considering this, it's probably much more effective to give a LOT of money and other assistance, but really a lot of both, to the minority of people who'd really want not 1 or 2 but 4, 5 or more kids. There still is enough of them in "First World" societies.