Planning has to be done based on the relationship between what we want and what we can accomplish. Based on principles and values of a society that allow investments that lead to a better future. Think of the time where people in the USA were optimistic and had a tendency to "think big" both in the public and private sector. Governments got involved in huge infrastructural projects like dams, highways/roads, levies, ports, and other related to communication including the space program. Private enterprise got into the military industry, aviation, and in general production of goods and supplies.
And then there was the mixed effort where cities like Portland OR were able to bring together the public and private sectors to set the parameters that would allow growth of the city while guaranteeing livability for its citizens. Nohad Toulan who passed away a few days ago due to a unfortunate car accident in South America is an example of leadership, you can read more about him here: http://www.oregonlive.com/opinion/index.ssf/2013/10/nohad_toulan_and_a_planned_por.html
This is an interesting video: