"To sum it up: Every single decision you make is entirely based on your personal preference, which you can't overlook. Humans will always seek for the greatest possible amount of profit through their actions, and whatever that profit consists of is based on that very same personal preference."
While I think your post is very interesting, I think you are discounting the critical roll of Altruism in human society.
If we all just thought and acted for ourselves, we would still be hanging in trees killing each other over food. There would be no charity, no medicine, no science, little need for language, and (sigh) NO computer games, graphics or consoles.
In life the self centered individual seems to be self limiting on how far they can advance. As the lead of a wolf pack, will get challenged regularly and eventually lose.
In recent studies scientist have been looking at what separates us from the rest of the animals and altruism is very rare in non-domestic or human influenced animals. The one exception might be ants – they are the dominate species on the planet is because of their society. A single ant can not do much on their own, but they work together and are amazing. (You could also argue they don’t have free will as so behavior is chemical and pheromones.)
Anyway, not sure if you’re a psychologist or social psychologist, but it might be your calling.