The above example just reinforces my perception that probably 80% (at a minimum) of illegal immigrants to the US are doing it for economic reasons.
And it is not just a US problem. in Bangkok, probably 50% of the staff in many restaurants are from Myanmar, Laos, or Cambodia that are (probably) working illegally. Same in the construction industry. And, there is a lot of Thai construction workers in Korea working illegally. In Thai, they are referred to as "little ghosts". Taiwan gets a lot of mainland Chinese working illegally.
"Follow the money"