Think about Mars as redundancy site for the human race.
So many of the industrial processes that we've developed assume a huge interconnected network of supplies. To make Mars self sufficient you'd have to reinvent a huge chunk of the modern industrial system while also trying to keep your small population of colonists from dying. It's a monumental challenge with today's technology.
Which is inversely correlated with the chances of it coming in any particular timeframe.
I'm the biggest fan of colonizing Mars, but my children know that if Daddy ever has the chance he is going to Mars to suffer, not to play. Mars will be hard and unforgiving. Life will be horrible for the first two generations at least. At no point will it ever be better than life on Earth.
And yet, I'll be the first in line.
This reminded me of computer tech in its first approximation: hard and unforgiving. It took about 2 generations to make it into a ubiquitous mobile device. In about four generations AI will make space colonies possible. "And AI shall produce acomodations for adventurous humans and preserve them". Space seems first and foremost the realm of AI, embodying our outreach. We won't actually go to space unless a planet is discovered and farmed to be hospitable.
Nuclear war is the big one. Mars colonization would be less about preserving human life, per se, and more about preserving an operational duplicate of the peak state of human civilization.
That’s the point.
Funny, but extremely high altitudes of the atmosphere of Venus could fit the bill in the context of places in the Solar System. Temperatures and pressures are around room temperature and pressure there. The thick atmosphere of Venus provides some radiation protection, and water can be extracted from the clouds of sulfuric acid droplets there. You couldn't directly breathe the air, but oxygen could be produced in-situ, and bags full of breathable atmosphere would be buoyant, so you could easily suspend cloud cities there just by using the atmosphere inside the environment domes.
People who have been thinking about this are way ahead of you. There are plenty of minerals on the surface. We should be able to build remotely piloted mining equipment using phase change materials (like water) to shed heat. To cool the equipment off, we just haul it back to the high altitude base before the phase change material tank runs dry.
Also a very tiny amount of people are working on space right now (maybe 500,000 between NASA, SpaceX, Blue Origin, ESA, ISRO, JAXA, etc). That's 0.00625% of the world's population.
It's hard to imagine there's an economic case for Mars or the Moon while Antarctica remains undeveloped.
https://en.wikipedia.org/wiki/Antarctic_Treaty_System
Not that there would be much going on without the treaties, but it would likely be commercially viable for oil exploration or maybe mining.
There are also other reasons. You can't learn about the possibility of life on other planets in Antartica, and seek to answer one of the greatest questions of all time: "are we alone?". You can't closely study another planet in Antartica. You can't be a brave new explorer seeing incredible places for the very first time in Antartica. There are far less new scientific and engineering challenges in Antartica whose solutions will greatly benefit everyone here on Earth. And so on.
Note, these things are true for any next-gen space endeavor in our corner of the solar system. It doesn't have to be Mars, or even just Mars. For example, we could build larger and more advanced facilities and machinery in LEO, while also building a small base on the moon and exploring Mars for the first time.
That's an argument against research on Antarctica, but that's the one thing humans do there.
I think settling Mars will and should happen, but anyone who doesn’t realise it will be thousands of times more expensive, risky and dependent on external support than eg Antarctica I think isn’t really grasping the difference in scale of the problem.
Wasn't there a fair bit of difficulty involved in building fleets of sailing ships and exploring the Earth? As it so happens, the reward for doing so was to become dominant in the new global geopolitical context. There's an incentive to keep up in the new expansion of context to keep from being left behind and engulfed in a larger context. The potential total population of the solar system, even based on just on foreseeable technologies, asteroid resources, and solar power could easily be in the hundreds of billions. Fusion power increases that potential by orders of magnitude.
It seems silly to be trying to rush to a place that wants to kill you when we have a great place here already that we could just stop messing up.
These aren't mutually exclusive things. And make no mistake: Many things involving ocean travel prior to the industrial revolution literally involved rushing to places that want to kill you, via another place that wants to kill you. Isn't rushing to a place that wants to kill you another kind of "doing things that don't scale (at first)?" If it means eventual geopolitical dominance in a future larger context, there will be wealthy nations willing to foot the bill.
https://www.quora.com/Why-did-USS-Constitution-bounce-cannon...
In Roman times, the British Isles were also a significant source of lead.
There is a good chance that creating the tech for the later will make the former possible, but not vice versa.