According to this article in Governing, some economists question whether population growth is always a good thing for cities.

Although the preponderance of media opinion has always been that more people make a better city, there has long existed a cluster of academics who challenge that wisdom. Perhaps the leading voice in this contrarian club is Paul Gottlieb, an economist at Rutgers University. He has argued for decades not only that local elected officials should take a measured approach to growth, but that metropolitan areas with stable or slow-growing populations are likely to have greater economic prosperity. Fifteen years ago, in a paper titled “Growth Without Growth,” Gottlieb called attention to 23 of the largest 100 metro areas, which he nicknamed “wealth builders.” Those were places with below-average increases in population and above-average increases in per capita income.

Another group of metro areas, which Gottlieb labeled “population magnets,” had excelled at gaining residents but performed below average at increasing per capita income. The data seemed to suggest that mayors shouldn’t frame future population increase as a guaranteed path to a better economy, especially when it comes at the cost of greater congestion, pollution and the loss of open space. “My paper was controversial in the sense that it questioned the desirability of population growth in any way,” Gottlieb says now. “It’s not obvious why you would want population growth except as a means to the end of increased income or increased wealth.”

It seems to me that bringing in more affluent taxpayers has to be good for a city as a whole, particularly legacy cities that have lost population density and have vacant, undermaintained housing and infrastructure. Of course it is not good for some residents in some neighborhoods if they feel as though the newcomers are concentrating and displacing them. I don’t have the answer to this any more than anyway else, except that providing excellent transportation and other infrastructure might tend to encourage people and well-paying jobs to spread out a bit more geographically. In Philadelphia, what is happening is that the newer, more affluent taxpayers are concentrating in neighborhoods closest to the central business district where they work, so they can walk, bike, or have a reasonable commute on public transportation to work. There will not be any lack of housing in Philadelphia as a whole any time soon, but the less affluent are getting pushed farther out from the city center and neighborhoods with good transportation links to the city center. Philadelphia actually made a plan for a comprehensive subway system a hundred years ago, built a small fraction of it, then stopped. Nobody has the imagination to even suggest finishing that system. We don’t even have the imagination to consider taking diesel buses offline in favor of the electric buses and trolleys we used to have, even as we have a serious air pollution problem. Schools and parks that have been in a state of disrepair for decades are very gradually improving in the more affluent neighborhoods, and continuing to languish in the less affluent ones. All this leads to tension between black and white, rich and poor, recent arrivals and long-time residents. Increased tax revenues could be invested to help solve these problems, but our politicians and bureaucrats just continue to fail us.