Do you have any idea how absolutely infeasible space mining water is at current tech levels? It costs about a $1,000/gram to send something to space.
Lets just say it doesn't cost any extra to bring it back. Right now gold is about $60/gram. We couldn't even mine a solid 24K gold meteor without going broke, and you want to do it with water?
I agree that it's retarded thinking we'll send people into space to mine fucking water of all things, and in general Earth has massive amounts of resources that are more than sufficient.
For the benefit of others, here is what my PhD in vidya and sci fi books has taught me:
The big expense of doing things in space is, of course, the huge amount of rocket fuel it takes to get up there. It takes a bunch of fuel due to the tyranny of the rocketry equation (the more fuel you add, the more fuel you need just to move that fuel, so like diminishing returns).
However, you can do things to cut down on this dramatically. If you produce as much of your goods up there as possible, you can minimize inputs (of expensive Earth-based launches) per output. Supposedly the chemical and industrial processes it would take to manufacture in space has already existed for a long time, so as long as you can make rocket fuel from water (which as I understand has still not been done, but is theoretically sound), you could potentially, with automation, get huge amounts of minerals for a small input of the little things that just can't be done up there. In the novel Delta-v, they build shitty barges from scratch out of their mined asteroid production, quite a bit like muh Mississippi River barges I ramble about on occasion, it's just a piece of shit you send one way and then bust up for salvage.
It takes tons of fuel to get up there, but perhaps not so much to get down. Have not heard any proposal, but I've thought before that you might do it through a controlled crash (if this is a one-way drop, literally drop it to Earth with minimal fuel or parachutes or whatever to slow it so it doesn't crack the Earth like a rod from god, then have a recovery team go in and get it; drop this shit on something like the Sahara).
Even the rocket fuel issue may be simplified if you have networks of railguns and recovery probes to catch the payloads they shoot.
Of course, just because the stuff is plentiful, that still doesn't mean that even with a possible way to do it cheaper that it would still be cheaper than just digging it out of the Earth. I also think the idea of permanent habitation in space is completely retarded, there is no reason to talk about settling people by the millions out there, the only value in it as far as I'm concerned is just a network to rip open those asteroids for their juicy innards.
