I responded to a comment here, but just to flesh out the point, Philly doesn't have an affordable housing problem. Philly has a poverty problem.
Lack of affordable housing becomes an issue when land prices increase greatly, increasing prices/rents generally and encouraging developers and landlords to develop and redevelop more upscale units. Land prices in much of Philly are still really cheap. We had decades of population loss, only just (maybe) reversed.
Whatever the merits of that development, it's proposed for an area that by any measure has lots of affordable housing already.
Now I'm all for helping poor people. I would give them all of Donald Trump's moneys and some of mine, too. But housing isn't unaffordable for poor people here because it's expensive, it's unaffordable because there are a lot of people living in poverty.