It's well worth watching Neil deGrasse Tyson on this: https://www.youtube.com/watch?v=0CJ8g8w1huc "The 3 Fears That Drive Us to Accomplish Extraordinary Things" - if you look closely, the actual successful colonization of North America was driven by private enterprise. I gave a talk on this topic at the last Mars Society convention, in case you are interested: https://www.youtube.com/watch?v=6BOOuGUnDek