Avent notes it's still there, however fast the suburbs are still growing:
Suburbs have seen massive housing growth and rapid population growth, but prices in central cities have soared, even in many places where population numbers are level or falling. If no one wanted to live in central cities, prices for homes there would not rise. And indeed, several decades ago, prices for homes in big central cities were dropping. But that trend has clearly reversed. You can't draw conclusions about demand shifts from population numbers alone. This is a very simple point, and yet its repeatedly ignored.
Derek Thompson has a related post on how "U.S. policy continues to support suburbanization over urbanization in countless ways."