Immigrants and the children of immigrants are also disproportionately likely to be productive citizens. I wouldn't be surprised if half the current Fortune 500 were founded by immigrants and the children of immigrants. (The figure for 2010 was 40%.) See my comment below. [3]
It's certainly possible that the majority of America's wealth is generated by relatively recent immigrants.
Of course, this is controlled immigration. No country anywhere lets just anybody in.
[1] http://www.vox.com/2015/7/9/8922783/immigrants-crime-donald-...
[2] https://www.americanimmigrationcouncil.org/research/criminal...