Until there is real consequence to sneaking across the border it's not going to stop.
If Uncle Jose left for the border, and nobody hears anything from him for the next 5 years because he's in a hard labor camp somewhere, the rest of them might think twice about doing it themselves.
Expecting illegals to not break the law by coming here (and then giving them free everything once here) is like leaving the door to the pantry open and expecting the rats not to come in because it's 'not right'.