Is that surprising or peculiar to the USA? Is it easy to become a citizen of Japan, or Germany? It is a general pattern that highly desirable destinations to live eventually fill up (by some metric chosen by the insiders) and close borders or are made undesirable.
Germany and Japan don't spew propaganda about them being built by immigrants or being a melting pot or something like that. US is, while at the same time having draconian immigration policies. I think that disconnect is interesting.
