The gap would already be dramatically reduced to within inches rather than metres. In effect it would be gone, although it would very literally be so if culture and conditions were rectified in a way that hasn't yet been tried in the United States over the past "150 years" (as if anything substantive was done in this time whatsoever). Of course, you can always disagree and argue from the basis of genetic determinism, but we all know the evidence for that is inconclusive and your "thinking" that it isn't won't make it anymore real.

Oh, and just to make clarion your intellectual dishonesty, what does all of this have to do with Founder immigration? Nothing. What is it really about? Probably racism.

Have a nice day.