What is wrong with leaving the city? Why should a magical line drawn on a map make a difference? Why do people want to make cities into insular bubbles that don't interact with the rest of the region? But commercial buildings in the suburbs, and residential buildings in the suburbs, and then people will live in the suburbs and have a higher quality of life than living in the city.
Or just stop teaching people that they must have a job in the city and no where else, get rid of parochialism. That's a major problem in so many cities. People want to be in the city limits even though it cames with more drawbacks than advantages, the demand makes the housing prices skyrocket, it drives out the middle class, it drives out people with families, it destroys the public schools, and the only reason for it is that some people care about having a desirable zip code.
In most places, that has already happened, then the new real estate "out of the city" becomes desirable, because the highly paid workers that work at the company that located outside the city want to live close to work. For example, Microsoft isn't located in Seattle itself, it is in Redmond. So Redmond real estate becomes pricier because all the borg drones want to live near the MS campus. All the tech companies aren't located in San Francisco, they are located in Silicon Valley so more housing is built there and so it becomes a massive nightmare of urban sprawl rather than the higher-density housing you get when the company locates within the city center. Amazon is a bit of an exception as it is located in Seattle proper, but many companies that are moving into a given area locate in the existing suburbs for many reasons (taxes, local workforce, cheaper real estate, etc.). In many (most?) cities the problem isn't gentrification driving lower income people out, it is all the well-off people (and many of the companies) moving to the outlying areas leaving mostly poorer people living in the city centers.