I think also part of it is simply people being more willing to empathize with someone they see as "their own". People tend to intuit that a full-time job should pay a person a living wage, and so if they're employing people that are in their social circle they'll give that to them (adjusted for the sky high inflation of living in the wealthy areas they live), but with someone from outside that circle it's a lot easier to compartmentalize and pay them less than that.