There is a finite and already fully utilized number of domiciles. Adding 400 well off families would undoubtedly displace 400 not so well off families over time

There is a finite and already fully utilized number of domiciles. Adding 400 well off families would undoubtedly displace 400 not so well off families over time. All while jacking up prices of apartments/food/services for everyone. Where is the positive net effect for people here? The city&state will earn more tax revenue, but for the neighborhood there's nothing positive that's going to happen.