Either all of Mexico can move to the US (probably not a winning solution) or we can make Mexico a safe and excellent country again, and that means getting rid of the cartel.
And yes, other countries have their issues too and we should help stabilize those countries as well.
If the Mexican government can fix their cartel issue, we can go back to normal remittances. Until then the US will make policy choices to resolve problems.
As always, the salt of the earth people will pay the cost for politicians being bad at things.