In Philly’s Center City live its richest residents—those who can pay the premium for that walkable, amenity-rich, green neighborhood. But just across the river, blocks away from the lush, expanding campuses of the University of Pennsylvania and Drexel University, the visual landscape of the city changes: Pawn shops, fast food eateries, boarded-up store fronts, and dilapidated houses. Only a few areas in West Philadelphia have become more prosperous (and whiter). The rest continue to suffer conce…