>No, total immigration matters. Human progress is always subject to the law large numbers.

Human change can be subject to the law of large numbers, but nothing necessitates any particular change being towards progress.

>Skilled polish engineers don't want to be the only polish person in the entire country. They want food, culture, community that reminds them of home. Even as they assimilate. That's why the American melting pot works well. It encourages enclaves that touch one another.

The American melting pot works well (or worked well) because it was a nation made up from a blank canvas with no prior historically established dominant ethnicity or culture the kind other nations have had going for millenia.

And even at that was built on first disenfranchizing (to put it midly) the natives.

>The American melting pot works well (or worked well) because it was a nation made up from a blank canvas with no prior historically established dominant ethnicity

That's a bit of an oversimplification. They were British colonies for well over 100 years before declaring independence. The US Census website states:

"Not surprisingly, the first census reported that based on the names of heads of families, more than 90% of the White population in 1790 hailed from British stock: English (83.5%), Scottish (6.7%) and Irish (1.6%)."

https://www.census.gov/library/stories/2023/12/boston-tea-pa...

>And even at that was built on first disenfranchizing (to put it midly) the natives.

Not many European colonial powers purchased land from natives the way the US did. For example, considering the Louisiana Purchase area, the US paid over 20x as much to natives living in that area as the US paid to France:

https://www.slate.com/articles/news_and_politics/history/201...

The US looks bad compared with a hypothetical (nonexistent) perfect country. But compared with European powers, it looks pretty good.