50 years ago people had the same loyalty towards their companies, and look where that got US manufacturing workers. nowadays you'd be nuts to expect to stick with a company for 10 years. get yours and get out: others be damned.
so it shall be with citizenship. as more and more citizens have more and more power to up and leave, or work outside the confines of the US without too much hassle, questions such as "what on earth are we still doing here?" will be asked, at first in whispers (as they are now), later in louder volumes.
where things go from there, anyone knows.