Two reasons: (1) They are being sold fantasies about how wonderful the US is, which don't reflect the reality of the life they will experience when they get he

Two reasons: (1) They are being sold fantasies about how wonderful the US is, which don't reflect the reality of the life they will experience when they get here. There's a massive industry built around smuggling, fake documentation, and relocation assistance for illegal immigrants in the US. They make a ton of money selling the "American Dream" to desperate people. (2) Even with a "low paying" job in the US, you still acquire an enormous amount of spending power in their home country, so remittances to family are extremely helpful. Often these people are coming from countries where $400-500 USD a month (or less) supports a family of 4-6 people.