If a young professional is willing and able to pay $3,000 a month for a unit, and a poor long-term resident is only willing and able to pay $2,000, renting to the former will lead to the more productive party gaining access to the high productivity neighbourhood.

If there is a 20% productivity boost from living in the high productivity location, and the young professional generates $12,000 a month in value, while the poor long-term resident generates $5,000 a month, allowing the young professional to outbid the poor long-term resident will lead to a $1,400 boost in monthly productivity.

That productivity boost in turn leads to more jobs created for more poor people.