“Considering that as many (if not more) are still entering the US illegally this seems to be a zero sum game to me.”
Not so much anymore. Their numbers are down to a relative trickle and more are actually going back voluntarily.
If the status of the 12 to 20 million illegals is legalized, they will in turn be able to sponsor an additional 66 million to 100 million more LEGAL immigrants thru chain migration, i.e., family reunification. The country will be destroyed with the stroke of a pen.
Surge Two: Northward Flood of Mexicans Likely to Increase after U.S. Election