I like to begin to say that the two of us will not be on the same page on this matter. Which I do not mind. Since I find you are an astonishing character, one, with which disagreement can be freely expressed without ending in the result of disliking and dismissing each other. I rarely meet people like you. So thank you for that openness of yours.
I hope, that I will be able to sufficiently lay out my train of thought in response to your response.
The immense gift of earthly conditions, i.e. the existing atmosphere, breathable air, flora and fauna, are all geological processes that the planet does all by itself and need no human hand in this great and whole for regulation, since regulation of climate and weather arises through the history of the earth and through ever ongoing events such as ebb and flow - the existence of huge oceans and their currents - mountains and their influences on valleys, natural fires etc. etc. without our intervention.
The very fact that we as humans do not need to do all this enables us to attend to those matters that are applied on a small scale to convert wild land into arable land, to divert water and use it for our purposes, to extract gas and oil from the earth's interior and much more. These earthly resources are the result of millions of years of geological evolution and cannot be produced artificially. These processes are cyclical processes; all living things and matter on this earth are subordinate to such a cyclical existence. To artificially create such a geo-biosphere would require us to constantly and exclusively deal with the regulation of the sphere.
While events that arise on this gigantic planet regulate death and live - under which human beings, just like all other animals and creatures are subordinate to - they will not do so in a closed system of a spaceship. Since a spaceship is not an ancient old geo-biological - in comparison to earth, being in space at the right time in the right galaxy for such perfect conditions - but a technological body and you cannot and will not have the same conditions, not even close.
By not even close, I mean that even small errors in the regulation of an artificial sphere that is trying to regulate organic life can lead to gigantic failures. As humans, we may have a good understanding of the impressive processes on our planet, but the devil is always hidden in the details.
What happens apart from our actions alone, where we neither observe nor intervene, this ‘man is there’ and ‘he is not there’, i.e. events that unfold untouched by us, provides the balance of the terrestrial in my eyes. In a spaceship, no matter the size, you'd have to regulate it 100 percent. Whereas now we need not doing any of the regulation. We just live gifted with a planet, that regulates itself 100 percent.
Earths regulation of all of its inhabitants and matter results, like you said, in volcanic eruptions and tsunamis and earth quakes, and these very events are one part of its ever changing nature. While it is for us humans catastrophic in the short run, it isn't for the planet, since drastic events are part of the great system and a requirement for the build up of raw materials and the growths of such resources, buried underneath its soils. Humans survive the semi huge catastrophes, if only in tiny numbers (like you mentioned), while they will die when mega impacts will occur. Who will mind that?
I have no problem with such an event since my mind will not live to suffer from it. No ones will.
In my view, all of this is a philosophical consideration. Whether we humans believe that we are rather exposed to misery on our earth, that the ‘narrowness’ of which you speak is not something that we could regulate ourselves or from which we should try to escape, since narrowness or vastness is a phenomenon, a psychological phenomenon that expresses itself in the eternal suffering of the self and human nature and absolutely wants to see this suffering disappear through action. The ‘departure to the promised land’ and ‘better worlds’.
Incidentally, this is an imperialist idea that I do not share, although something of it always resonates in every human being.
The idea that the lack - and not the self-evidence of human good company - makes it a valued asset again is, I think, also born from the idea of being able to control such things. The creation of an artificial lack, which then automatically leads to the cancellation of becoming or being tired of each other.
I think this is a misconception, because being tired of each other needs not have to do with the narrowness and abundance of human conspecifics - as I think - but can, for example, have to do with one's own age and the years that have passed. Young people are not usually tormented by the fact that they get tired of each other's company, although they may have little love for an ageing group that outnumbers them.
Confinement is not a given on our planet per se; those who dislike living in confined spaces (big cities) have options to change this. Even if it's just retreating into your four walls as the simplest of all alternatives. If they don't, they must and will endure it. But there are folks who have chosen living apart from big cities. So they may not perceive such ghastly unwanted company in the same sense.
In general, this confinement - where it exists - will also disappear of its own accord; we have long since initiated the trend towards a low birth rate.
I maintain that the perception of confinement and freedom depend entirely on the mentality and may have nothing to do with the actual conditions, but with the will respective unwillingness to adapt to realities.
So I take the freedom to turn your assumption around and claim that although you have constructed a gigantic space-ship, man, aware of the metallic outer walls of this ship, feels just as confined as on the much larger earth, the far more 'perfect' spaceship. On which one man feels that the earths regulating itself is a very heavy burden, while another man feels at ease towards it and appreciates the fact of not having to be burdened by it. You can feel trapped and become hostile towards other people even though they might be your one and only company.
There, lies the difference between acceptance of creation (apart from mans will) and the will of construction (including that very will). The ever lasting conflict between human beings.
One mind suffers great sadness in the face of his mortality and also bemoans the total disappearance of the human species itself, while another mind finds itself at ease with it and accepts both, his own death as well as that of all human beings as the natural cycle of life itself. With no need to escape it.
For the one death is an ego affront, for the other it is liberation. Since death is not seen as "the end" but something other but incomprehensible and un-explainable. Nothing to fear and to escape from. But to give oneself into.
This does by all means not express that such a believer would not fight teeth and claw for his life when directly threatened, I shall add. Or that such person will not want to live when facing illness. It's an acceptance in general but not in particular.