We all know it’s not going to be 5 million, not even in the first year. It will be basically anyone that crosses the borders, and that huge number would multiply.
If the government tells you 5 million you can bet its going to be more like 15 - 20 million. Bear in mind we have over 300 million pople in the U.S. it’s almost like adding almost another 1/10th to the population