The sociological problems are *the* obstacle to what you want, if you haven't been reading this thread at all.
Really? Because from what I've been reading, it seems that the scenario where the rich are immortal demigods living in space and the poor don't even have clean drinking water is not only possible, but alarmingly probable.
Describe to me how you find this posit significantly different from, say, all of human history?
Genuine, raw numbers, resource scarcity is a fairly new problem. For most of human history, the problem with resources wasn't so much a hard lack of anything, as it was acquiring what was already available. Heck, look at aboriginal societies - ever tool and object they desired could be found in abundance laying around on the ground. And they still made war on each other, they still had social hierarchies and to some extent a concept of wealth. Same sort of things apply to manufacturing capacity. There's significant evidence that the average medieval peasant only worked about five hours a day, but availability of resources didn't prevent conflict. When computerized industrial manufacturing took off, people predicted the rise of the four-day work week and shorter hours. Instead, human working time remained the same, but productivity increased. Throughout all of human history, increases in production power and availability of resources have never, ever led to a reduction in competition over them. What they lead to is greater wealth, not a ceiling on want or any increase in satisfaction. No matter how much is available, everyone always wants more.
As long as we're still talking about actual human beings, human societies will always suffer from human problems, brought on by human nature. We are, as individuals and societies, greedy, be it greedy for wealth, or power, or in this thread's case longevity and intellectual dominion. And I have yet to hear any satisfactory or even theoretically feasible solution to the human condition, save the absolute removal of humans.