I agree with 95% of what you say, the other 5% is of small things.

Because of the way our bodies are made we will probably need more oxygen with decreased preasure, see http://www.OneMinuteCure.com.

Plus I have concerns about a no rules society, as the society develops there will be new sets of rules to keep society from melting down.

Help will always be available in one manner or the other, everybody should be trained in First Aid and rescue techniques.

As the population grows, specialization will grow, but there will always be some "Jack of all trades" types to help out. And then there will be "Guilds" develop to control quantity and quality.

Craig