During the last year of the housing fraud bubble, there were ads touting 110% LTV mortgages on very expensive homes, available to almost anyone. The median dodgy mortgage is probably pretty small, but the average could have been pushed pretty high by those outright fraudulent mortgages which are probably worth less than $0.25 on the dollar and may, once the occupants are done with the property, be worth less than $0.01 on the dollar.
The typical illegal alien lives in a house with a dozen other people, rides a bicycle, eats at Burger King (once a day), and sends as much money home as he or she can ~ usually half.
Even the nasty guys have feelings for their relatives back home so they regularly send half that's left over after basic living expenses.
Not a real good life. So far haven't met any of them who really wants to stay here ~ they'd rather be rich and down home.
They are undoubtedly ripe for assimilation.