Cartel stuff has been around for 20 years, it's absolutely impressive how fast everything went to shit but that's kinda the point, it was fast, unexpected, and brutal. Mexico's murder rate was dropping until 2008 where it spiked like a motherfucker. I don't think we'd be doing as much buisness as we do with Mexico if we didn't have the inheritance of the good decades before 2008, but now we're sorta forced to continue trading and working with them due to the fact that a significant chunk of the buisnessses in border states are deeply tied to the shithole down the border, and you can't disengage that without hurting the bottom line which is ultimately the only thing that matters for US elections. Greg Abbott tried to shut down the Texan border and was basically stabbed in the back by the truckers, the farmers, the manufacturing sector, everyone in Texas needed that border acccepting trucks in a speedy fashion and that caused him to just give up 3 days into the whole mess.
Don't know if this speaks to the fundamentals but it is not true that this was a problem since forever, or else we would not have stuff like NAFTA, and Mexico would be more to us like how Africa is to the Europeans.