To my post yesterday, my wife asked, "What about on a small scale, such as each family? What if a family ran for what is best as a whole instead of just each for himself?"
Certainly, I think certain elements of society can definitely run for the interest of a subset group. A family is a great example where individuals sacrifice their wants and needs for the sake of the group - such as a mother sacrificing career goals for the sake of being home with a child, or a husband working fewer hours at the office that might advance his career so he can be more available to his family. I think that's a fine example where communal interest can be worked toward to achieve a greater whole.
The problem not addressed in socialism in general, and not addressed in Galaxia effectively, is the need for a common goal or cause. Simply wanting a better world doesn't work for a lot of people. If that better world means that someone must have a smaller house, drive a smaller car, eat less, work harder, or myriad other things, then that someone is likely to shirk. Shirking, simply means failing to do one's best in this context. If working harder (or generating more, however that is best described) will not directly benefit the person putting for the effort, that person is less likely to continue the extended effort. Karl Marx certainly overlooked the key element of the society he based the Communist Manifesto on: he studied a monastery and how well it functioned by working for the sake of the whole, but then he removed faith from the equation, which was the glue that bound their efforts together.
In the novel, the reason for Galaxia was to create a system that removed waste as much as possible, or more correctly removed excess. By removing the waste, the system would achieve a higher state (I believe the scientific term is entropy). At the very end, a reason that might justify the need to work together is presented, but it felt very tacked on to me (not to criticize a master, just my observation). Removing that onerous threat from the equation - a threat which most would deny or ignore anyway - I have trouble believing people would subjugate themselves to such a system willingly.
So, once again, socialism sounds wonderful in the ideal. "We're in this together!" is a great slogan. Or Rodney King's famous "Can't we all just... get along?" The problem is, the selfish nature of humanity is involved - and I am not convinced that it is a bad thing to have in the equation. Throughout the series, the characters acknowledge that society begins to decay when greatness reaches a level at which no one feels compelled to strive for "more" - whatever more might be. Scientific innovation tends to come from a need observed. If society is perfectly satisfying - or extremely satisfying with few shortcomings - then why would anyone worry about improving it? Certainly the world today is far from perfect, so people will continue to work for a better tomorrow. But if they cannot hope to reap the benefits of that "better" and that "more" then why should anyone expect them to try for it?
So returning to my wife's point, I can absolutely see sacrificing my own needs for the sake of my children. I can eat less to provide more for them. I can drive a minivan for their comfort instead of cramming their little legs into the back of a sports car I might want (or in my case, perhaps a small pickup). I just have trouble believing anyone else will necessarily sacrifice for them, and I have trouble asking them (my children) to sacrifice for someone else who may or may not be putting forth their best effort. I have trouble believing anyone else is willing to sacrifice for me and for my family. Instead, what we get is a lot of shirking.
Pure capitalism may not be an answer to any of these problems, but from an academically economic standpoint, it is hard to argue for socialism in practice - at least when practiced on a large scale, and whenever it is put in without a common goal. Correction: a commonly accepted goal. Without the agreed focus, the smaller players in the system are more likely to work in their own interests (to quote Seinfeld, "not that there's anything wrong with that...").