Sigh, to sum up my arguments:
1) Governments are not going to sponsor colonization efforts. It takes tax money that can be utilized elswhere, and risks creating an independent and competiting political entity down the line. It is simply not (usually) in their best interest to establish off world colonies. Short of a major catastrophy, its a bad idea and will be seen as a waste. Look at the space programs in the present day and the fights for even minimal funding.
2) Corporation will want their colonies to be as self sufficient as possible to attract colonists, i.e. workers, and also to reduce its own overhead. A dependent colony that has to import the basic necessities of life is going to be far more expensive, and that reduces profit and incentive to establish in the first place. A dependent colony is more at risk of destabilization from a missed shipment, than an independent one. And the more risky a colony is, the more you have to pay people to work that colony.
Independent colonies are the difference between paying large salaries and high prices for support, and selling land to colonists, and lower price for support. Between higher overhead and less profits, and lower overhead and higher profits.
3) That leaves organizations such as the Church of Cousin Marrying, or other philosophical separatists movements. Their very act of separating them from the home world indicates a desire for independence from that home world. And you are not independent if they are shipping you vital supplies on a regular basis.
For self sufficiency to be achieved, that means that the vital things, such as food, water, shelter and air have to be created in situ. To do this independent of the home world, that requires being careful about just what tech you bring with you. There are a number of ways to do this that I can see.
Low Teching: Going back to tech level 3 is not as bad as some folks are making it out to be. The example of Australia given above is really an invalid one, because it was started by a tech level 3 civilization to begin with. We are talking of an age of square rigged wooden ships, gunpowder flint lock weapons, horse drawn steel plows and the like.
It should be noted that this is the beginning of the industrial revolution, which would be impossible without a surplus of non-farm labor to begin with. Food production efficiencies had already started to improve prior to this, which is one reason why the industrial revolution was able to happen at all.
Many modern technologies, for example the Bermuda rig sailing ship, can also be constructed using 18th century technology and materials. There are other examples where our technical knowledge would translate using simpler materials.
And, more importantly, it would be only temporary, as a lot of technical knowledge we have already achieved, knowledge that is easily transportable, even if it is in paper books. The wheel does not have to be invented from scratch, as we already know how to build such things as computers, power plants, digital watches and the like. This would allow the independent colony to take off a lot faster than our own civilization did.
Right teching: Make the equipment you take along rugged and where possible field repairable. The addition of a machine shop can greatly aid the maintenence of such technology, and make the tech level fall far less. Having a machine shop that can duplicate itself, as well as a power supply, bringing that stuff in the initial colonization plan, would greatly reduce the risks, and would make the colony more profitable overall.
Biotech: This is where I think the food argument breaks down (which is really a combination of two arguments and will be dealt with below) Higher yeilding crops, as just one example, will reduce the amount of labor required to farm, amount of acrage required to feed the colony. Items such as horses are self replicating, and to some extent self repairable. And by tinkering with the genetics, you can improve on these facets of such creatures to ensure that off world support is not needed.
One point should be stressed, is that none of these three proposals are exclusive of any other. You can do all three.
Food production labor: At the beginning of the American Revolution 19 farmers fed 20 people. The argument appears to be that a self sufficient colony would also require an near identical ratio of farm labor, to the rest of the work force. I have already shown several ways around this above. This is not necessarily true.
Also, farm labor is idle during large chunks of the year. During plowing and planting, as well as harvesting, the labor needs is highest. But during the summer and winter, their is little labor needed. This is why historically wars were fought in the summer, after crops were planted, because of the extra labor available for military actions.
Since the colony is not (generally speaking) at war, that labor can be applied to other projects, such as mining and manufacturing, if required. And thereby boost the tech level of the colony.
It should be noted that recent Bureau of Labor Statistics for the USA show 2.053 million workers in farm and agriculture related jobs out of a total job force of 138.556 million. Even if you assume the entire 9.82 million production workers are ALL building stuff to supply the farm industry, and no exports of any food stuffs, you still have 1 farmer (and related industry worker) feeding 11 1/2 people. Hopefully you can see that my assumptions mean the farmer and those in related fields are feeding far more than that.
Yes they are using modern tech level 8 equipment. But if we already know how to get 1 farmer to feed 11 people, the idea that we would revert back to the pre-Revolutionary war ratio of 19 farmers to 20 people seems a bit ludicrous. Especially considering the work arounds I have provided above.
Yes, it is going to require a special kind of person to be willing to go to such a colony world. But outside of some form of slavery, a colony is going to have a self selecting population to begin with. Folks who think they have the right stuff or who want to get away from the home world.
In our own history, this has meant mostly the peasant classes immigrating. The aristocracy and a lot of the bourgeois stayed in Europe, as they had it far better off than the peasant class. They came here for a number of reasons, mostly for a better life free from the political control. To a large extent, they were extremely successful, in an incredibly short time frame. European civilization may stretch back over 2000 years, but most of the technical advances since then have been the result of the efforts of the population of one nation, on only 200 years.
Part of this was due to political ideals, especially the concepts of individual freedom (no matter how poorly enacted, especially in the slave holding south) And yes, that colony did not lose contact with its motherlands for any extended time. However now that former colony leads the world in technical advancement, and per capita productivity. Its economy is larger than the next 6 nations combined, despite having far fewer people than several of its competitors, and despite existing for a far shorter time.
I can't help thinking that part of the resistence to the idea of a self sufficient colony might have something to do with this latter facet, that America was settled mostly by peasants, and succeeded beyond the wildest dreams of anyone, without the overriding hand of an aristocracy. The very idea that free stupid peasants can lead their own lives, and do far better than their "betters" in Europe, has to be galling to some. America has proven that an aristocracy is superflous at best, and parasitical drain, even an impediment to technical advancement at worst. We did not do anything that any other nation could not have done, far sooner, far earlier in history. But they did not, and we did.
Its not a question of manpower. Its a question of brain power, and whether you utilize all the brain power of a colony, or whether the few subjugate the many, preventing them from developing their own ideas and technical innovations. That is probably the key factor here more than anything else, including which technologies are brought to the colony world in the first place.
Bureau of Labor statistics can be found here:
http://www.bls.gov/news.release/empsit.t10.htm
There's far, far, FAR more to technology and production than you can see from your cubicle in the IT department.
