Depends whether or not the city allows other neighbourhoods to exist/grow/change. If the total floorspace in the city is fixed in regulations, then ofc anything done to improve conditions will hurt people on the bottom. The people who can afford a "revitalized neighbourhood" would happily live in brand new housing built on top of land in the nearby mansion district, displacing no one, but city planners do not allow that - new apartments can only be added to the city stock by destroying old ones, new store floorspace can only be added by destroying old etc. This forces everyone to play musical chairs with too few chairs and the only winners are those who own the chairs.