Nader Elhefnawy remains skeptical. But I think he misses one of the strongest drivers, only mentioning it once, almost in passing:

Such miseries as famine, war, and persecution cannot be ruled out in the future, of course, but they are hardly a likely driver of space development. In fact, given the extraordinary economic demands that any space development effort will make, it may be much more practical for a prospering world than one suffering through such disasters to undertake such efforts in any foreseeable future.

Emphasis mine. One of these things is not like the other. One can have persecution in the midst of prosperity, and that combination may well result in emigration, just as it did from England to the Americas in the seventeenth century, and from the American east to Utah in the nineteenth. I think that a combination of a desire for freedom in concert with evolving technology is the most likely driver for human migration into space. Unless we’ve all uploaded ourselves first.

[Late morning update]

Clark Lindsey doesn’t buy Elhefnawy’s thesis:

If there existed large O’Neill habitats today, there would be no problem in attracting tens of thousands or even a few million people to move to them. The number will depend on the cost of getting there but when talking about a fraction of a percent of the world’s population, you can find that many people to do virtually anything. The excitement of building a new world in the new environment of space will be charm enough to attract large numbers of people.

Of course, the trick is finding a way of getting from where we are today to a point where building large habitats becomes feasible. I agree that such progress will not be attained by individuals heading out into the last frontier in their own spaceships. But that does not mean that individual action is not the essential element in making it happen. Even if one buys the revisionist view that the expansion into the American West was primarily due to “railroads and speculators, [] logging companies and mining concerns”, one should remember the fact that these organizations were made up of individuals who took huge personal risks. Many, if not most, of those companies and concerns failed and took down all the individuals involved with them. Similarly today the individuals involved in a private entrepreneurial space start-up are taking huge risks with their careers and investments. Many, if not most, of those firms will fail. The people involved know the risks but they make the effort anyway. That is the nature of tough endeavors on earth and it is the same for space.

Of course, perhaps the biggest question is whether modern culture and government will allow, let alone encourage, such risk taking.