but even the recent immigrants who have become permanent residents mostly oppose higher level of immigration.
In the US, this seems to do less with politics and more with how much immigration is going to affect your own standard of living. People in high-paying cushy jobs - or close to retirement - don't seem to care as much.
There's a Chinese story about a city bus that's running packed. A man begs the driver to let him on, and then turns around to another man trying to get on behind him and says 'Get off. This bus is full'.