Earlier quoted context omitted.
That is economically illiterate. If it got to the point where there was not enough people to fill necessary jobs around the city the wages would rise to attract more people. Right now the opposite is happening: there are too many people.
Too many people? Are you serious? San Francisco + Silicon valley has 3 million people. That's less than half of New York City. The amount of money the region makes is more than enough to support that population over that area...
So, if 86,000 is "poor" (defined as the minimum needed to live in the area), the person doing the food preparation has to be paid at least that. The "burger flipper" has to be paid that.
If people moved out, quickly the "burger flipper WOULD be paid that". But that, in turn, would attract "burger flippers" who simply compare the money. Resulting in high unemployment, and the need for food banks again.
Its the concentration of rich people that is the problem.