The debate about immigration often focuses on fear of crime coming into USA. Fear that may, or may not be legitimate. To me, that's not the main issue. The big issue is accommodating population.
We can accommodate more. It could even have benefits for work that needs workers, prosperity that needs consumers and culture than needs vitality.
Problem is, we have to make changes in the way we live, here in USA. Acres of free parking may have to go. Housing density needs to increase in some areas. The Southwest states are on the verge of running out of fresh water.
In some ways, we could live more fulfilling lives than we live now with the isolation and alienation of today's culture, but we have to be willing to make some big changes.
Population does have it's limits depending on how we live.