The reality is very different from what it was in the 17th, 18th, 19th & even early 20th Century America. We are vastly more crowded, with still limited resources.
As for the jobs Americans do not want nonsense; that assumes that it is better to have millions happily on Welfare, SSI or whatever, at the expense of the rest of us, while the jobs that those on the dole could be handling are given to foreigners with no interest whatsoever in preserving that settler driven culture of America. It is so obviously a stupid argument, that we should educate our would be "educators" from Congress to peddle their folly somewhere else.
For a discussion of the real issues over immigration, including the reason that Jefferson bought Louisiana: Immigration & The American Future.
William Flax
in other words
Become Meh-e-Co