By '10 years' in a hermetically sealed box I meant an experiment on Earth to understand the inputs/outputs so we could give scientific and engineering advice when something goes wrong in the Mars biosphere. Biosphere 2 failed for unforeseen circumstances. This experiment would also be a good way to select for the kind of people capable of being the first explorers.
You need to bootstrap the process but due to changes of government, economic troubles, you have a finite window in which to scale successfully. Building that biosphere becomes important fast.
Even the most exacting monarchs had limited control over what happened in the colonies due to distance and time. The further you extend your reach, the more autonomy you have to give to the peripheral. It's like a law of nature.
Talking of giving up control there's a funny book by Wernher von Braun (of German rocket science fame) where he claims the leader of the Martians will be called 'Elon'. I wouldn't have believed it if I had not seen it.