I have explained this to a group of anti-immigrant people, who, to their credit, actually Got It.
Relatively prosperous American women are no longer having two children. Unless we start importing people to do what immigrants have always done.
Quit with this byzantine visa process. Let people come here, pass a health test, get a work visa card - and go home when they want to.
We need those workers.
https://econofact.org/the-mystery-of-the-declining-u-s-birth-rate