To do this, the U.S. would have to:
Idiocracy just turned 15, and in the opening scene, a yuppie couple keeps explaining why it's not the right time to have kids while the trailer parkers keep pumping them out. People who have no money or stability don't hesitate to have kids while people who are professionally employed tend to hesitate like crazy.
Perhaps the trailer parkers have solved the equation for affordable housing and now have the resources to support larger families? Maybe it's the career professionals in trendy suburbs working long hours to pay for empty bedrooms who are on a never-ending and meaningless hedonic treadmill. The trailer parkers are accomplishing a life goal and creating a legacy, while the yuppies are simply burning time and money. Who is really smarter?
People who have no money or stability don't hesitate to have kids while people who are professionally employed tend to hesitate like crazy.
@ChpBstrd, would it be fair to summarize your list of ways to increase the birth rate as "lower housing costs, free education, free health care, free childcare"? Because I agree all of those are barriers to having children, but if we look at many parts of Europe that have those things, birth rates are still low (and even lower if you discount children born to immigrant mothers) and continuing to decline.
Housing is extraordinarily expensive compared to income in many parts of Western Europe, and the unemployment rate is routinely above 10% in multiple Western European countries. The social safety nets are often better than in the U.S, and transportation is more affordable, but it appears lots of people still struggle to afford tiny apartments. The same could be said of Japan and South Korea.
Still, people made due and had large families in the past, even amid all sorts of uncertainties and with tiny housing. Perhaps the real issue isn't the lack of an empty bedroom or seat in the SUV that a kid could occupy, it's that people value other things more than having kids - namely money and stuff that can buy us individually-enjoyable experiences. We take for granted that there was a time when one could work their ass off and still not enjoy air conditioning, automotive travel, fancy restaurant food, electronics, or resort vacations. In that world, people's joy was expected to come from other people in their proximity, which is a value set juxtaposed with our current status quo of expecting joy to come from imported manufactured objects, tech devices, or the aspiration to live in a prestigious "gated community" where the neighbors in this supposed community don't even know one another and contribute nothing but their purchase price. Those of us aspiring to FIRE expect our joy to come from having more autonomy over our time, which is itself a modern luxury, enabled by financial products which didn't exist a few generations ago. Bottom line, it's all about us. We're more individualistic than ever before, and more skeptical that collectives like families can work out. The concrete and immediate sense of reward we get from money and stuff seems a more solid bet than hoping to feel more satisfaction than disappointment about prospective kids someday.
I might edit my laundry list of proposed changes with a caveat: These changes can only reduce the relative cost of having a family versus other directions one can take with one's time/money. The changes would persuade more people on the margins to have more kids. However, just as getting a coupon does not guarantee I will buy something, these discounts will fail to close the gap for some number of people. For those who simply don't value the idea of having a large family, a large family will never be cheap enough, just like a Rolex will never be cheap enough for me to buy one. It is what we value, not just price, that determines what we pursue.
I have 6 kids, so definitely at the far right end of the bell curve on family size in the US (households of 7+, i.e. 5 or more kids, represent about 1-2% of US households). It was a very conscious decision early in our relationship that my wife was going to be a stay at home mom and I needed to be able to provide for our family on a single income. ... That meant making trade-offs about buying a house, buying newer cars, taking vacations, eating at restaurants, etc. Kids are expensive. Not so much the feeding and clothing them, but the fact that we live in a 5-bedroom house instead of a one-bedroom apartment. We own a large van that gets 10 miles per gallon to fit 8 people - many of whom are in car seats.
Here's an example of someone who is optimizing for something other than FIRE ***OR*** hedonic consumerism.
@Michael in ABQ is trading both wealth and luxury for the experience and consequences of having a large family. It's a lifestyle choice, just like FIRE is a lifestyle choice, working until you're 70 to buy a new car every 3 years is a lifestyle choice, and so on. A consumerist might criticize Michael's lack of lifestyle luxuries, a person dedicated to hardcore FIRE might criticize his finances, and Michael might criticize them both for living their lives for the sake of money and stuff instead of surrounding themselves with unconditional love. This imagined disagreement illustrates something Adam Smith noted centuries ago - all value is relative.