The population of the US in 1950 was 150 million and last year we passed 300 million so adding 150 million in 50 years is not much of a stretch. By the way there are a heck of a lot of Iowa and Kansas farm towns that have been deserted and could use a little immigration. Might find that immigration would be great for the MS. gulf coast and New Orleans too.
Don't worry.
Once all the better places to live are OVERCROWDED with people, whose every decision and movement must be regulated by the bureaucracy of cities: laws, penalties (lest they get in each other's way), and more taxes to pay for it all . . .
Those who know better will flee to the flat and boring and deserted Iowa and Kansas farm towns, wisely judging such miserable places to live better than a once beautiful seacoast become crowded with people and development and government regulation.
As long as they're legal I agree.
I'm in Louisiana. I want NO to just go away.