I agree let the pressure build until the pot blows
Nixon was well aware of this in the 70s, fearing that the climate in Mexico was ripe for communism, something which he felt had to be quelched at all costs. We could not have another Fidel controlling Mexico, our southern neighbor.
Until Mexico gets its own house in order, something I believe won't happen, the exodus will continue. The majority in the USA is too soft and will also do nothing (but the lefties and capitalists will continue to suppport illegal aliens for their own ends).
For a country which prides itself on strength, Mexico is one complete rat hole.