(For previous parts in the series, see here.)
For all that we think we live in a free market, the truth is that we plan all the time. As Matt Yglesias and others have pointed out, zoning is planning, and so is licensing of certain kinds of businesses (bars, restaurants, etc.) and all the other kinds of regulations that are so ground-level they become almost invisible.
The problem is that the kind of planning we do is fragmented, not systematic, unconscious not conscious (or at least not openly conscious – consider how bans on multiple-occupancy dwellings in suburbs are sold as “protecting housing values” as opposed to “keeping out poor people”, and not particularly intelligent.
And this won’t change until we start to learn from our actions.