This seems to be the real danger to Mexico of reduced exportation of the poor to the US. More domestic poor, more discontent, more pressure on the government. The border has always been used by the corrupt Mexican government as a pressure relief valve to keep the ruling elites in power and the poor safely in their place. They’ve also relied on the billions sent south as a revenue stream for the government. The only true immigration reform for the US is a total reform of the Mexican style of government.
If it were up to Trump I suspect he’d do a speech to that effect, but the repercussions would be fairly immediate and unpredictable. It’s coming eventually anyway, might as well get it over with. Mexico’s a narcostate run by an elite kleptocracy. They are as corrupt as it gets.