Well before 1882, the United States had a completely open border. Anyone could enter at any time. There were some rules in place to expel certain people, but anyone could come. And the first quota was the Chinese exclusion act of 1882, born out of pure racism of the Chinese.
Ellis island opened in 1891. At that time they only excluded the sick and known criminals.
It wasn’t until 1921 that general quotas were put in place.
So you’re right it wasn’t 150 years, it was only 145. If you don’t count the 150 years before that when we were a British colony with open borders.
And billions would not come to the US. The poorest person in the US is still in the top 15% worldwide. So unless you’re one of the 1 billion in that group you probably aren’t coming here. And of those one billion, 400 million already live here and many of the rest live in Europe and have it better there than here. So no I’m not worried about it. They would still need a job or they would t survive long.
Israel is a special case, but yeah I think they should have secure borders with no quota too.
Polar bear populations are fine, sea level had been rising at the same rate for much longer than we've been industrialized, storm rate isn't changing, and where do you live that there are no insects?