We'll never get to the profitable stage if we don't go through an unprofitable stage first, though. Besides, each dollar spent provides a much larger impact to the economy, so there would probably be short-term benefits as well.
1) We understand the concept of investing for the future. That is not our issue. Our issue is that it's a bad investment.
Oh? There's a few important resources that are easy to get on other worlds, including one that we've completely run out of here.
2) While it's true that space exploration leads to economic impacts we could more benefits from targets closer to earth.
Perhaps. Depends on how well the colonies turn out and what "targets" you're talking about.
Think about the Scottish colony at Panama. It wasn't an inherently bad idea. But they jumped the gun and tried to make a colony with woefully inadequate tools. The result was that they expended a lot of effort and got none of the benefits that a more viable colony would have given them. Mars will happen if we continue to develop our ability to explore space. But sending a bunch of underequiped colonists to die won't help. It will just set us back.
Agreed...but we DO have the tools. Really, the only obstacles will be volunteers and radiation at this point.
As for minerals, well asteroids are easier than Mars. And robotic mine don't sound that hard. Remember, robotic doesn't mean entirely automated, once the asteroid is parked in orbit, you can remote-control the minebot. And since bots don't need stuff like air, food or vacations down on earth, they're much cheaper and effective.
However...what happens when it all breaks down?
As for land, I can't imagine a time when settling the Sahara would be harder than settling Mars. Having an athmosphere and protection from cosmic ray is pretty awesome. Or settling Siberia. We still got plenty of space on Earth when you think about it. And population is set to peak at 10 billions, so we're actually fine.
1. Mars is still bigger, and right on top of some great deposits of various minerals where you won't have to worry about the environment or neighbors or anything.
2. The Earth can't really support the 7 billions it has now, even assuming you're right...
Also, having humans just make everything more complicated. You might send them up once in a while, to fix somthing, but why on earth would you want a fully functional space station?
Simplicity. Also, to alleviate concern on Earth about robots functioning without human guidance. Assuming we're going farther than the Moon to look for asteroids (which are pretty uncommon around here), there's probably going to be a delay measurable in hours...
If we are going for asteroid mining the material we would want the most is water. This is very simple indeed to mine, you just melt it down and filter it.
Unless we're setting up colonies, not a lot of need for water. Clean water? Sure, but a lot more than mining can provide, and mostly to areas which aren't suited for regular deliveries of asteroid water. Fuel use? I suppose that's useful, but I think that various metals would be considered more valuable.
We haven't considered the mass nerd migration factor. Whether that is worth it's last savory denizens is an interesting question.
Not just nerds. People who are bored of their dull lives; people reminiscing of colonial days; adventurous people; entrepreneurs; etc.