It turns out the real border wall was the friends we made along the way.
That is: if auto workers are being paid that minimum wage by foreign automakers, that's gonna be a massive boon to Mexican household incomes, which improves the standard of living for at least some people, and in a dramatic way. This money will, I reckon, go straight toward things like entrepreneurship, higher education, and other things that help with upward mobility on a generational scale. This can (and I hope will) translate to less emigration pressure, since fewer Mexicans will feel the need to move north for US wages if they're already being paid US wages, and fewer migrants from further south will feel the need to continue across the US/Mexico border if they could instead settle in Mexico for similar pay and much lower cost of living. This could persist long-term, since a better-educated and more innovative population can give the Mexican economy one hell of a jumpstart (and, importantly, help whip up a generation of Mexicans with the technical education to keep up with the inevitable automation push).
I'm curious how this will play out long term, but it seems reasonable to me that we should pay workers according to the value they create rather than merely the cheapest employers can get away with paying (and contrary to what the far-capitalists might claim, these are rarely if ever in sync, especially when talking about outsourced labor; a worker in Mexico is not inherently worth different than a worker in the US, so why should those two workers be paid differently?), and I'm oddly optimistic about how this might play out.