One reason (that few seem to be discussing) that Mexico will likely *never* significantly slow the flow of illegals- Apparently, the government only controls about 30% of national territory and 20% of population centers. The rest is either cartel-controlled or "disputed".
Source: Map: The military deployment of the National Guard in 266 coordinations (google translate)
Source: Map: The military deployment of the National Guard in 266 coordinations (google translate)