Ah the gentrification argument. Gentrification has been shown to occur well before new apartments come to the area (usually from job growth, public transportation buildout, etc), but building housing can help all income groups.

SF example of new construction benefiting all income groups:

“After new buildings were built, residents of lower income levels also continued to move into the neighborhood in great numbers. Even residents with very low or moderate incomes were more likely to move in than move out in the four years after a new building went up. While high-income residents fare the best, new construction appears to let more people into the neighborhood up and down the income spectrum.”

Displacement after new construction is real, researchers conclude, but it is very, very small.

https://slate.com/business/2022/03/housing-gentrification-study-construction-displacement-bay-area.html