Yet it will continue happening, and will happen on Mars as well, because humans are -- quite literally -- born to procreate more humans. Children are also supremely adaptable and some (but not all) will prosper even in the toughest circumstances.
>>Even if terraforming ever works, it will take centuries. Dozens of generations.
That's not a stopping criteria, even if it is something to consider. A long trip starts with a single step. If there is no plan to make human interplanetary species, then this safeguard will never ever begin. If there is a plan, sure humans will become interplanetary. Even if that plan is on the scale of decades and centuries.
PS. I do not understand why bots and humans cannot live side by side on Mars. Furthermore, with a huge selections of bots, humans will have access to a lot more space. So they will not be subject to a submarine-like environment.
PSS. It is also a matter of scale. If 100 people move to Mars, their life will be harsh. If 100k people move to Mars, together with selection of bots, their life can be reasonable.
To answer your question at the end, I think it comes down to risk vs reward.
> why not just wait
We can wait, that's an option that's less costly, but more risky.
If something planet-scale happens while we wait on a single planet, the entire species would not make it. If we don't wait and pay the extra price of going to multiple planets sooner, the species has a better chance of survival in the case of such an event.
On the other hand, the list of disasters that would leave Earth less inhabitable than Mars without also destroying any Mars colony is pretty rare. If human survival is the primary goal, it might be best to work on perfecting that sort of self contained habitat somewhere in the remote parts of Earth.
I suspect even Musk doesn't believe this. I've never read/heard him talk about our species being wiped out. He usually prefers the much more vague concept of end of our "technological civilization".
I think there is a strong humanitarian argument for making life multi-planetary in order to safeguard the existence of humanity in the event that something catastrophic were to happen, in which case being poor or having a disease would be irrelevant, because humanity would be extinct.
I think there are really two fundamental paths. History is going to bifurcate along two directions. One path is we stay on Earth forever, and then there will be some eventual extinction event. I do not have an immediate doomsday prophecy, but eventually, history suggests, there will be some doomsday event. The alternative is to become a space-bearing civilization and a multi-planetary species, which I hope you would agree is the right way to go.
Either we spread Earth to other planets, or we risk going extinct. An extinction event is inevitable and we’re increasingly doing ourselves in.
... along the timescale of millions of years. Dinosaurs lived for over 100 million years. What a load of rubbish.
That's a reasonable view too, IMO. If our technological civilization suddenly collapses for any reason, most of us here, and double-digit percentage of world population, will die a painful death. The lives of whoever remains won't be pleasant, and the technological civilization probably won't arise again for tens of thousands of years (given how we've used up all easily accessible energy sources).
Life is very resilient. Humanity as we know it is not.
> spending a week in Death Valley will look like an incredibly attractive prospect for them, but even dying of exposure [to germs, I suppose] there will be utterly out of reach.
Those children will be born in a small room, surrounded by metal and aluminum, maybe a blow-up shelter, and will never once in their life leave those surroundings. They will never once breathe fresh air. They will live and die in an area of a total size of perhaps a small football field, divided into minimal rooms (so there'd be as many of them as possible), with minimal energy.
And that's just the beginning. From what we've seen happening to astronauts it is blatantly obvious that you do not want to subject a growing human body to gravity even slightly different from earth surface, to do otherwise will at the very least have serious consequences for their bones. It is likely in the extreme that it'll have extreme medical consequences amounting to serious physical handicaps, even if they are born on the surface of Mars. If they are born in zero gravity, it seems unlikely that they'll ever even see adulthood.
But if they survive, it'll be in a small compound. Metal and stone around them, all the time, everywhere, and not much of it. Accidents will be as lethal as they are on a submarine and therefore they'll require the iron discipline (including the rare to occasional decision to leave someone behind to drown/suffocate when the situation requires it). They will be locked into this situation by physics, with absolutely no way to fix it. Even if terraforming ever works, it will take centuries. Dozens of generations. They won't just be old when things change, they will never live long enough to see children that will set a foot outside. They will see DVDs, and will get the phenomenon we see in the third world. DVD players showing them the vast fjords of Norway. The immense flats in middle America. And let's be realistic here: spending a week in Death Valley will look like an incredibly attractive prospect for them, but even dying of exposure there will be utterly out of reach.
Let's face facts here: these people will have lives that solitary confined prisoners would not trade place with.
We are the ones, along with their parents, who will have "done this" to them. Their parents will be forgiven, as they have made a mistake, listening to the misrepresentations of people like Elon Musk. We, however, "could fix this", with incredibly massive energy expenditure to get a few thousand people back from another planet, and we'll choose not to. Why not ? It'll make the Moon landings look incredibly cheap, hell it'll make WWII look incredibly cheap, and even if we do it, it'll take decades for the transport to actually happen. Even if we choose to have a kid come back, the kid won't be back until (s)he's in their forties at least.
We are probably a decade, maybe 2 or 3 removed from having built "general AI" individuals, who would have no more trouble walking in robot bodies on Mars or Venus than we do on earth. As in, a bit of planning would be required, and you'd do well to have some basic preparations and shelter ready, but failing that will be unpleasant, not deadly, and it would take weeks of exposure and deprivation to kill them. Besides, such individuals would be programs walking around in robot bodies. If they really got into trouble they could just transmit themselves to safety.
Since these will easily colonize the solar system, and humans won't, not now, not ever, even if we manage to get a tiny Mars colony going, why not just wait ? Bots, AIs, cylons, machines, or whatever we choose to call these individuals will far outnumber people on Mars (Given the surface size, a Mars colony should expand to about 6 billion people, but it will take a little under 1500 years to get to that point, so even if we start with 1000 individuals (100 is more likely), machines will start to colonize Mars (and other planets) when there's less than 10k humans)