Huh?In your world, Google, PayPal and literally dozens of massive American companies in the tech sector would be foreign companies. Elon Musk had done nothing prior to paypal, same for Sergei Brin at Google, what if they didn't meet "your satisfaction" to be one of the 6? I'm guessing that two college kids with funny names wouldn't have met your criteria.
Sergei Brin came to this country as a child, not a college student. His father is a Professor of Mathematics at the University of Maryland and his mother is a research scientist at NASA, so yes, they likely make this a better country for having admitted them. Not to mention the fact that you are completely leaving out Larry Page's contributions to founding Google.
And Elon Musk had founded, grown, and sold a company (Zip2) to Compaq for $300 million before he founded X.Com, which eventually merged with Confinity. Confinity's founders had developed and released PayPal in 1999, Musk acquired it through the merger 2000.