You know what encourages illegal immigration the most? I mean really encourages them.
The $15hr they can make by coming here. The government has destroyed the value of our currency so much, that even though it's a poverty wage for us ($15hr), it's a gold mine to them. Many places in Mexico, S. American and others places, $5 to $10 per day is their normal wages.
Do the math. Say $8 per day for 30 days.... That's 240 a month.
They can make as much in 2 days here, as in a month in their own country.
If the tides were turned, between the US economy (wages) and Mexico, we'd be sneaking across their borders too. Because it would just as impossible to change our government & economy as it is for them.