But you are right that it is ending, just wrong about what: it’s the high economic activity that attracted people which is disappearing thanks to the same people that hate migrants.
I'm not sure there's a "just" here: compared to peer countries, the US is either middle-of-the-pack[1] or significantly more accepting of immigrants[2] depending on which number you pick.
(This isn't to somehow imply that the US isn't hostile to its immigrants, because it is. But the question is whether it's more hostile.)
[1]: https://www.visualcapitalist.com/charted-the-share-of-foreig...
[2]: https://www.oecd.org/en/data/indicators/stocks-of-foreign-bo...
By the way, your [2] is useless to prove your point: you can't compare absolute numbers (for instance Iceland vs the US).
(Again, I must emphasize that this does not make the US good. Only that the bar is perhaps lower than people who are assimilated into any particular country may realize.)
1. the amount of violence directed against immigrants legally allowed in by governmental forces.
2. the chance of legally allowed in immigrants will have immigration status changed without due process.
3. what percentage of Immigrants fear that 1 or 2 will happen to them.
I believe these two conditions seem to exist in the United States currently, although not sure how many immigrants it affects.
I am unsure if there are other countries that have a similar situation, I would expect if there are they must be relatively few in number.
The closest type of situation would be, I suppose, racial oppression focused on particular groups that have become undesirable according to a country's government.