As individuals, a lot of people are content to live a simple life of prosperity. They have a basic job, and a small family, and some basic luxuries - and they call it enough. Some people have a one-eyed focus on increasing their wealth throughout their lives; but not everyone is like that. People generally recognise that their lives are finite. Some try to aim for some kind of imaginary high-score in their life, and others just live a 'normal' life.

I'm now making an analogy. As a species, we can recognise that are time is finite; and we can choose to live that out in a stable simple prosperity, where we just look after our world (house) and get what we need for some basic luxuries, and be content. We could have a billion years of that. It's a very long time. Or... we could aim for endless growth. We could consume as much as possible, and always aim for more. As we run out of resources and livable habitat on Earth, we must look to interstellar travel and spread to other planets. I don't necessarily think that is a better choice.

When I was young, I use to think that humans needed to settle on other planets. But I don't think that any more. Partially because I learnt about special relativity, and decided that unless we're very very wrong about science so far, having connected colonies on other planets is not possible. But also because I realised that there is no intrinsic goal to spread human life as much as possible. There are other things of value. We don't need that particular goal. I also use to think that personal immortality would be a good thing. I don't really think that any more.