There will come a day when immigrants are courted and encouraged to relocate in America. It won't be hard, although getting the right kind immigrants may be a challenge.
The world wide fertility rate continues to fall. In China, for example, the reported birth rate of 1.3 is at an historic low, and Chinese officials are worried. China’s new births are likely to fall below 10 million in the next few years, with a fertility rate lower than Japan’s and perhaps the lowest in the world, according to
this article.
For an interesting discussion, Google up "China Demographic Time Bomb" and read some of the numerous articles. Most of them discuss the problems that are coming with an aging and shrinking population.
America remains the destination of choice for desperate people. We should hope it remains the destination of choice for ambitious, hard working people, too.