Unusual Thought
I totally agree that North America would see a population decline if we stopped immigration. But unfortunately we need young tax payers to pay for US Social Security and the Canada Pension Plan.
If these things were run by qualified insurance companies, the money would be there from our past contributions. But our contributions have gone into the ether maybe to fight a war or develop the F-35 Fighter Jet. If this happened in a private insurance company, people would have gone to jail.