...is that expanding in to space is so freaking expensive that there does not seem to be any way to make it turn a profit.
...space industrialization and colonization are both incidental to rather than central to the human enterprise of space.
You'd think futurists would be more visionary. You can turn a profit and colonization is central.
Then there's the absurd argument that you need millions of people for industry. Millions of people allow for more efficiency. They aren't required to enable. That just requires a handful of people with the right skills. People seem to have these absurd blinders until somebody comes along and shows them how it's done. Why is it... if they can't imagine it, it becomes impossible?
[A NASA] study found it would cost NASA between $1.7 billion and $4 billion to develop and build the same Falcon 9 launch vehicle that cost SpaceX $390 million. In its analysis, NASA says it had verified the SpaceX cost figures.
A side point is that there operations costs are also low like their development costs.
So people say it can't be done until it's less freaking expensive. Why does this assertion drive me mad? Because it's not true. Obviously, lower cost is better. No argument there. SpaceX demonstrates how we get those lower costs. By individual initiative. Moaning about lower costs does not make them happen. Someone has to take the initiative and make it happen. It's not about costs, it's about profit. Profit can be had at current costs which will lower over time making it more profitable.
Mars has about 144 million square kilometer of real estate that currently has a value close to zero. Value is not intrinsic, it is determined by people. People determine value by wanting something and by how much it costs them to get it. It doesn't matter if you don't want to live on mars. It just matters that some people do.
So if you had an underground mansion on mars with shirtsleeve surface gardens and life support for a number of people in a self sufficient community (with malls and community centers) and could get there for free (and I'll show how) suddenly that near zero value plot of land would be worth something more. It would have a market value.
People have some weird ideas about self sufficiency thinking it requires magic self replicating technology and millions of people. It doesn't. What it does require is a core of machinery and skills that are a self sufficient ecology capable of reproducing themselves and potential capability of producing all other things. This requires a few dozen skilled people, not millions. Having more people just makes it easier. Before SpaceX scaled up for production purposes they had about a hundred people making there first rockets. Sure they bought stuff meaning other people were part of the process. They did it because it made sense to do so, not because they had to. Choices should not be confused with capability.
How do colonists get to mars for free considering a mission will cost billions? I suggest a settlement charter that provides value to companies that transport colonists for free. This charter establishes an agreed upon law of the land. It doesn't require the approval of governments because this is virgin territory. Governments do not own this unclaimed property nor the people that would claim it. The colonists will make this legal by their combined actions supported by historical precedent.
Why would these companies do this for worthless land even if for millions of hectares? Because it's value will go up as more people get to mars. They just have to look past a quarterly report. Some companies do. Elon has repeatedly said it is his goal to get 10,000 people to mars. That'll do it. A few billion dollars is not cheap, but some are willing to take that risk and that's all it will take. If they ever do get the transportation costs down near the $500k per person they claim is possible then the argument against will evaporate. 1000 sq. km. per person delivered would then be a gold mine of profit.
What about the life of colonists? Some think it would be bleak but they aren't seeing it clearly. People will have freedom and the resources for great achievements. They wont have to convince the captain of some space ship to go someplace they want... they can just get into their own car and drive. A car that is easily produced and repaired, built by a handful of skilled workers that get the job done even if it isn't the model of the future. A car that runs on locally produced fuel from the martian air. Every single person going to mars, all of them, will have millions of dollars in assets to finance their dreams if they accept a settlement charter that makes that happen. This isn't the far future. This is the next few decades beginning now.
After the first few dozen being supplied from earth the colony will grow and expand. After a few hundred or thousands, people will specialize in a thriving integrated economy where people can focus on their passions without a government telling them where they can spit. It's a whole new world that will be part of an entire solar system economy. They will not be alone. I might live to see it start.