You're making this far more complicated than it is.
Regardless of whether a population is growing, shrinking, or stabilized, everyone will be doing what needs done to ensure their continued survival. Or they won't survive. The more people, the more commerce is needed to sustain them. Therefor, more production, more jobs, and more money moving around. Less, people, less commerce is required to sustain them, and so less production, fewer jobs, and less money moving around. But it's ok because everyone is still surviving.
An influx of new people is only problematic if the physical environment cannot sustain them. But if that were the case, they would not come. However, there can be a time lag between the new people showing up and the community expanding it's sustaining commercial enterprise to accommodate them. And this is why the Feds gave Spribgfield Ohio federal aid to help the incoming Haitians and the existing community to survive until the sustaining commercial systems could expand to sustain this new increase in population.
And this was all properly considered and agreeable to all.
Unfortunately, this is the U.S.A., where capitalism is allowed to run amok because it has long ago corrupted everything and everyone it's touched. So a very rich predatory private equity group had begun buying up all the housing in and around Springfield, Ohio to create both an affordable housing shortage and a monopoly on housing that they could use to price gouge the community for every dollar they could get out of them, and all that money left the community, never to return. Leaving the local commercial economy starved, and the people broke, even with the federal aid to the Haitians.
The economic equilibrium of the community was destroyed because predatory capitalists were allowed to pillage it at will. And it's not just Springfield, Ohio. It's all the other towns in Ohio, and in Michigan, and in every other state across the country. Hundreds of billions of dollars are being pillaged from communities all across the country, never to return. Leaving those local economies broke and economically unsustainable.
As a result we are now seeing homeless camps springing up all across the country. And thousands of smaller towns being completely wiped out. Falling to ruin by drugs, crime, poverty, and hopelessness. Predatory capitalism is decimating our country and killing our people, and we remain oblivious to it. And do nothing to stop it. Because we all have been taught to believe that greed is good. That it motivates progress.
The problem was never the influx of new people. That just takes a little time and support for our communities and local economies to expand to accommodate them. The problem is that big piles of money are being assembled and used to pillage the whole country by predatory capital investor groups. And some of you reading this have unwittingly given them your life savings to use to destroy your own communities. While you continue to vote for politicians that turn a blind eye to their criminal behavior.