I'm a Utopian idealist - prove me wrong!

I believe I have been misguided in your original goal. If this one is to state that those changes could be made with the current state of technology in the next decades, I will have to agree with it. After all, promising technologies are indeed being researched. However, if you believe that it will be DONE in the next few decades, then I will have to strongly disagree, as per simple reasoning and the consideration of human nature thorough it. --ENERGY PRODUCTION-- First of all, the problem with oil is that it is needed for many countries which lacks the money to change to otherwise. Notable examples of these would be China and India. If they would ever decide to put in use your theory, creating energetic infrastructures for a mere 2 billions inhabitants, (more or less) is not an what we could call an "open-source project." First of all, it needs considerable funds to implement the alternative energy source, and a large numbers of those sources cannot be used everywhere. As for example, you need a strong current river and a fairly large amount of plain land to achieve hydroelectric barrages, and once again, they do cost much more than what those countries can afford. As for nuclear energy, it does have several downsides, such as constant human monitoring, as I doubt we would trust automatic systems to watch over a potentially radiation catastrophe. Also, nuclear defect's need space and special conditions to be stored, and we do not know the full extent of environmental impacts the liberation of those defects into the soil could have. --JOBS AND SELF-MAINTENANCE ISSUES-- On this side, most of the technology that are required will entertain heavy research cost and operating cost until they are fully implemented. And there is no guarantee (we're quite far away from it actually) that it will come to a potentially lucrative technology in the next decades. Even with fully automated systems, you still need an human operator that will need to supervise that last part of the chain. I am forced to agree with you that we could achieve a leisure society this way. However, hundreds of domains, notably cinematic, music, art design and such do still need human creativity to be achieved. If money is retired, there will be no point in having an individual that is forced to work for other's entertainment. Not to mention the years of training those domains require. My last point will be in link with security issues. As I already stated, if one fall into a cardiac arrest before your own eyes, you cannot hope to save him with knowledge that is related to Internet only. You would need medical facilities, most of them which cannot be automated unless incredible advance in the A.I. technology (We are talking about centuries, or even more), and the same problem applies: Why would one decide to work if it is to provide security for his neighbourhood , while those are having some leisure time, from morning to evening? The same problematics applies for other security related jobs, such as policeman, judges, advocates, etc. --WATER ISSUES-- On this side, I would agree with you. Modernized countries with funds have no problem with water extraction, as they can afford the high cost. Passing seawater through a nanotube filter does not require money nor extravagant amount of time. However, producing a nanotube filter require advanced technologies that are quite costly and not accessible to all. Of course, the raw materials for the said filters are easy to find and to process. We still have an interesting problem: The creation of those tubes is incredibly complex due to the required size and as such requires advanced facilities. Once again, having those facilities at everyone's disposal is not what I would call an "open-source project." --POPULATION AND FOOD ISSUES-- We are currently 8 billions (More or less) individuals on Earth. And nothing indicates that the population growth will stop someday. If we base ourself on the fact that someday we will be forced to use more than what Earth can offer (Due to population growth, not to mention lack of space to establish residence), both in resources and food, you will be forced to find an alternative solution to it than: "Find a way to exploit the grounds". Now, it is true that we could sustain more than 80 billions people with experimental technology and maximized utilization of EVERY arable land on Earth, along with modifications of POSSIBLE arable land. Before this pay off, it would once again use an huge amount of resource and money. Now, the main problem with arable land is that most of it is underneath civilization and residences. Do you propose to relocate population so that we can use their lands to farm? Also, this problem is directly linked with overpopulation. The more of us are there, the more land we need to establish. However, unless you consider establishing residence in hostile environment, the problem will only get worse with time --CONCLUSION-- Your theory is inviable in the next few decades as it would require hundreds of change in actual industries, jobs along with security and enternainement-related departments. Those changes would then require massive funds and cannot considered as "open-source projects", making the whole theory fall apart, at least for the next decades.