The Oregonian published a modest story highlighting the economic diversity of the Pearl District, a well known urban renewal project. I was surprised at how many negative comments the story drew. Apparently it tweaked some people's noses to learn that poor people can live in the Pearl.
There are a lot of reasons to like or dislike urban renewal, but let's look at the most basic consequence. Urban renewal added housing. Between 2000 and 2010 the two census tracts which most match the Pearl added more than 5,000 units of housing. And it didn't add it willy-nilly, it was concentrated within an area of 0.72 square miles, most of it reclaimed from industrial and commercial use.
Now consider what would happen without such concentrated development. 5,000 units equals 50 100-unit apartment buildings. Given the problems the east side has shown accepting multi-unit housing, how would nimby leaders feel about 50 additional big buildings heading their way? Or you could suppose that demand would have been met with suburban housing. Assuming the same housing density as Beaverton that would require developing over 1,500 acres of land.
There are only so many ways of dealing with a rising population and a corresponding demand for housing. Urban renewal has its flaws, but if you don't allow multi-family housing in existing neighborhoods and you don't want sprawl then reclaiming land from other uses (and the subsidies that go with it) is what is left.