Lets see, when a country is invaded with an alien population that is so large that their culture overcomes the existing culture, that country will fall. It hasn't to do with the numbers of people, it has to do with whether the culture has members that will keep it alive. So flood the country with people who have no concept of liberty and its preservation by a constitutional government, and voila! no more USA. This in fact, is what the globalists at the WTO want because then it can manage trade to the most minute detail (a concept championed by the Soviet Union by the way)and not have to deal with the unruly citizens of an independent nation. Its best for the WTO if we're all just consumers and don't have any affection for our nation, anyway.
Just because you can make a buck off of a flood of immigrants doesn't mean that it is going to help preserve your country. The two things are unrelated in that context.