It's more accurate to say it got there by "embracing" slave and cheap immigrant labor. The South provided most of the fuel that ran America's engine for a good long while...and then we had the Irish, Italian, and Eastern European immigrants later on. Don't forget who built the railroads, either. Something tells me it would have been quite a bit harder to rise to greatest-country-on-Earth status were it not for these developments. Profits are always higher when you don't have to pay the help.
This continues to happen. One of the reasons don't "tighten" our borders. It does'nt help when you have Grey Davis give illegls Drivers Licenses and insist they get a pass on Community College expense. I think we both know the economic impact of "not letting wetbacks across the border". It would be huge. I dont agree with this but I dont see it changing