I was thinking about this a bit more. In my first answer, I was talking about what would actually happen if you got rid of money. But the question implies that people are suddenly altruistic ("pool our collective resources"). The problem with this is how you decide who should do what. And it might turn out that the situation posited ("without worrying about who owes whom?") is impossible in principle. Even to keep things going as they are now, someone needs to decide what needs to be done and by whom. Someone needs to decide who should give you the things you need to survive, and how much to give you. All of that implies that someone is saying "A should give X to B" and this is just a way of worrying about who owes whom what.
Yeah, part of what I was intending in the scenario would be that everyone realizes that we could make much faster technological advances (At least, that's the theory) if we didn't bother with keeping track of who owes who. We need resources such as metals, we get them, make the MacGuffin, and continue.
I suppose the real problem with this is some form of a game-plan, determining who needs what. So I guess what I'm thinking is a system that would require some flawless AGI to determine what group needs what resource at what time, to further the general human...
How much money would it take to engineer biological immortality for at least half of the world's population, within 20 years, with 99% confidence?