I'm a true native Californian and can assure you from personal observation that if you are enforcing the borders only the bolder ones will continue coming across. I have discussed this with amnestied Mexicans that I have known since the mid 1980's. The guys will come, but leave the family home. This encourages them to work for a while then return home to their families. They don't just setup house here like they are doing now.
Maybe you are right, but as you admit, the problem doesn't go away. In fact, with unattached males in the US, the problem of crime becomes worse.