According to this report, the EU and the US need migrants to ensure their populations do not decline:
https://deutsche-wirtschafts-nachrichten.de/2018/06/24/falsche-feindbilder-ohne-migranten-hat-europa-keine-chance/ [translation required]
I agree with the numbers, but this really is a false argument. Why do I say this?
The inexorable global growth of robots and AI is continuing to destroy jobs for humans. The reality is that in a few decades (perhaps earlier) there will be no way for the populations of the EU and the US to support themselves, so why don't we just allow their numbers to naturally decline?
Any sane assessment must admit that for this planet to survive the number of humans MUST decline. So why aren't we addressing THAT problem, which clearly is the 800 pound gorilla in the room?
Or do the rich have some secret program to address this which they're not willing to talk about?