While I agree with much of this opinion piece, I am hesitant to share the optimism about human nature.
I think he has it right that most of our history has been the result of competition among various groups of humans for limited resources. But, his expectations for "unlimited" resources in space seems extremely naïve, for 2 reasons.
First, there will definitely be limits on resources we can acquire in space. Those limits are not just from limited amounts of something being there at all, but more so the limits on our abilities to extract them from wherever they are and get them to the places where those on Earth and elsewhere actually need them.
But, more importantly, the reasons that we are feeling limited by the availability of resources that we need is that we have an inbred nature to expand our population, and we do so for as long as there are resources available to support the expansion. Then we fight others to take their resources, using all sorts of arguments to divide into "us" and "them" as the designated appropriate winners and losers.
And, there will always be a tendency for some individuals to seek control and dominance. Maybe we can select the first generation of colonists for some remote outpost such as a Mars colony. But, once reproduction is occurring at self-sustaining levels in any colony, the variety of individual attitudes there will become far less controllable.
What is needed is a change in culture that can deal with the negative aspects of human nature. It is naive to think that can all be accomplished with just positive means - only "carrots", no "sticks". And, the use of negative means requires some sorts of authority, which opens the door for repression and domination by the ones who have such tendencies.
So, while we seem to be making some progress as a species trying to civilize ourselves, I note that the worst behaviors are still occurring in our world, today, and are not being successfully suppressed.
I think we are going to have to deal with that for some time to come, as we create new colonies far from Earth, that must not only be able to support themselves, but must be able to control themselves in order to survive.