Thanks for the thoughtful reply. I agree about humans adapting to low gravity, but I do think at that point you have to accept post humanism to do so. How many people are willing to raise offspring knowing they are essentially committing themselves to creating a separate branch of humanity? That hasn't happened in a few hundred thousand years. Also, many of the people who have been swayed lately into supporting space settlement have followed Musk's personal arguement that it will provide a backup of the human species. But will it be human, really? At the same time, Im not sure everyone in Mars would want to hop in the centrifuge for a couple of hours for their daily constitutional.
Venus' lack of material resource could be a large technical problem. Getting resources from the surface without some huge leap in technology is mostly a non-starter, but Venusians would have as much access to NEO asteroids as Earth would. Apart from Mars, none of these potential colonies are going to be getting most of what they need from foreign gravity wells. The cost is too great. Venus CAN obtain quite a bit from atmorpheric gasses, however, and those it has in abundance. Still, it would remain materials poor. So is Japan, but it manages to still be a manufacturing power.
I guess in the end though it ultimately means, if everything you need for settlement is in the asteroids, go there and build colonies en situ. O'neill was right.
It's not that Venus is without advantages, of course. Knock enough rocks into it and you can both shorten the day and strip the atmosphere off; or a variety of other things. Compared to Mars, a Terraformed Venus is far more attractive to us baseline Humans.
The problem is terraforming it. If it's not fast enough (and I do believe it can be done quickly, again, it's always will, tech, and specie), then it'll be abandoned or given over to some other form of humanity, and that's their gig.
I'm not going to wave Venus off, of course, it's just that 'floating city' Venus is far more restrictive than Low-G Mars - for now. We'll probably see a base on Venus by the end of the century, at least, I would bet on that. It's just that doing anything else with Venus falls short. You could make a space elevator there, I believe, with current technology (but also on the Moon, which is my bet as well - the moon will see the first space elevators, attached to the pole and equator, as it's 'doable' with current level tech), and a few other things my groggy self can't quite remember right now.
As for the Post/Transhuman thing, sure, but that's mostly due to lack of public imagination. Scifi has inundated us with to much of the same old humans, just in weird uniforms, going around doing things, when it'll be bots, it'll be post-humans, cyborgs, doing all the like. Think if every Rubber-forehead Alien in Star Trek was just a human genetic offshoot: that's probably more akin to the near-middle future, than anything else. A Martian Tweak, for example, has two holes in the nose for more air circulation, or a space-adapted human basically has replaced their feet with hands to grab on to things more, and the like.
Already, Musk's (and Zubrin, and others) whole 'egg in different baskets' thing can be done with Orbitals, Habitats, the like. Mars isn't attractive, it's not Earth 2, and I do think there's a big risk that we'll get 'bored' with Mars after any 2030/2040 mission, just like with the Moon post A-11, A-13. It's just not that great. Sure Napoleon Complex nations will launch sporadic missions but my view of the future has been tempered by the constant ongoing danger and disappointment of this Terran reality....
