Government, state and federal, has retained ownership of land where the public trust values seemed to be higher than the benefits of private ownership. Government owns land to provide sites for publicly owned housing, and maintenance yards for public transit systems. Government owns land, and restricts the use of privately owned land, for a simple reason. Land is the skeleton, and the circulatory system of a community. It is the blood and bones of our society.
Land lies next to other land.
Its use, or abuse, effects everyone. My back yard is the view out your window. The traffic that flows to the shopping center clogs the streets of its neighbors. If I destroy a bald eagle nesting site on my wood lot, I am destroying everyone's eagles. If I erect a fast food restaurant next to your house, your property values go down.