This problem is compounded by dropping birthrates and the increasing need for working-age people. Many European countries are at risk of deindustrialization in a few decades. Even though there are problems with assimilating migrants in America, we are really lucky to be a settler society.
One thing they need to do is make having children appear a more attractive prospect - right wingers are fond of moral exhortations that this should happen, whilst making the objective conditions for doing so significantly worse. The Handmaid's Tale is a warning, not something to aspire to.
The 'people aren't having children because of the economy' take doesn't make any sense. The fertility rate is always higher in poorer countries than it is richer ones, and within rich societies themselves, the poor have children at a higher rate than the economically well off.
It does make sense, turning it the other way around. In a poorer country, having lots of children is an investment in the future. It’s likely to make your family better off and bring advantages in the long-term, while the opposite is true for most people in richer countries, where it is mostly a burden. The working and middle classes that struggle to make ends meet almost exclusively face financial disincentives, although the very top wealth percentiles do have comparable or even superior rates to the poor thanks to having the means to raise them comfortably.
The dramatic improvement in living standards over the past century has been a much larger driving factor in the collapse of birth rates than any change in social values. It’s also why today even countries with developing economies are experiencing decreases in the amount of children being born, as people in them get gradually lifted out of extreme poverty.