The financing of an offworld base is still very much unknown.
Even with a high volume and relatively low cost launch vehicle, the actual offworld base will be hugely expensive, and no commercial enterprise can realistically expect to make a return for their investors.
A government needs to step up with the rationale that it will eventually form a tax-producing colony - but a huge investment will need to be put in till it gets there.
We've had an in-orbit base for over 20 years without any claim of future tax revenue or commercial viability. On Earth, we have a long history of establishing research bases in places where there is no potential for a viable colony (e.g. Antarctica).
All we need is the political will and we can fund a Mars base as a purely government funded research program.
2. Another stepping stone to exploring further interesting/important space goals, like gathering resources from the asteroid belt/moons of jupiter/etc, discovering life on Europa, and so on
Money is just a medium for the exchange of goods or services. What would the colony export in order to generate the revenue required to produce said taxes?
The only sensible thing that would produce Earth based revenues would be some kind of intellectual property, but I don't know what is both sustainable enough and valuable enough to fund a colony.
EDIT: this is also made worse by the fact that the first few colonists should be farmers, mechanics and doctors (aka human mechanics), since all the intellectual work can be done on earth.
I expect that when we have a colony on Mars, exports will be found. Either mineral deposits which are rare on earth, or manufacturing processes which are easier with lower gravity.
A human being able to lift 3x as much without machines already opens up possibilities for greater productivity.
Stuff that must happen in the cold is cheaper to do too...
Think of Vegas - no economic output at all, tourist destination alone. Mars could do the same.
It only takes one thing - there is no need for a mixed economy.
I'm skeptical of that. Mars may indeed have some small advantages over Earth in certain niches of mining or manufacturing, but it's hard to imagine how those advantages wouldn't be greatly outweighed by the added difficulty of doing... just about anything on an uninhabitable planet, and expense of shipping the final product back to earth.
My skepticism comes from a different direction. Assume there's something that can be done at lowest cost on Mars — is it cheaper to send humans to do it (with all the necessary life support, radiation protection, and the inevitable black swans because we've never done anything like this before), or to figure out how to fully automate it and send robots?
If it takes 10,000 people to make $thing, then even at Musk's target price of $100k/person, the cost to develop and ship the automation[0] only has to come in less than a billion dollars to win.
[0] I guess the TCO would be more complex to determine, as the human side includes not just paying the humans (and presumably shipping good from Earth), but also figuring out how to do low-gravity and zero-gravity healthcare and surgery (on this scale there will be emergencies requiring surgery during transit), and planning for the colonists' desire to start families and retire.
The amount of money that a sizable and well funded group of people spend to get away from literally every other human on the planet and away from the government would easily fill a few rockets.
2. Martian Water.
Imagine all the disenfranchised homeopathics now have another woo-woo cure to turn to and will pay out the wazoo for. Make up a claim like "the purest water, untouched by human industry or nuclear tests, powered by billions of years of energy from sun, unfiltered by ozone and untouched by magnetism."
3. Tourism.
Vegas is basically a Martian tourist destination with an entire city built to support it. There's no other reason for Vegas to exist. If the accommodations were nicer, people would go to Antarctica as well. Rich people want to take their selfies with Olympus Mons in the background.
4. Low-G sports
Earth sports probably won't work the same, so entire new sports and leagues will form and provide entirely new season pass resell opportunities for streaming video providers. There's no way to simulate the low-gravity on Earth.
Also rich people sports like golf might take on an entire new ultra elite form when your par-4 hole 8 is 4500m long and you need a satellite to spot your ball.
5. Low-G food products
For similar reasons as the Martian water. Insert any combination of differences in nutrition/taste/look and it'll find it's way onto the plates of a three star Michelin restaurant or as supplements sold at a health store or something.
That's off the top of my head and could easily be a multiple billions of dollars per year of sustained economic output from Mars, mostly built on simple vices, novelty, entertainment, and pure human gullibility.
One way interstellar colonies could finance themselves, including no-faster-than-light financial systems is explored in Charles Stross' Saturn's Children books.
I expect it will be profitable in the future as it scales up. But there is probably only about 2x more scaling at the current price point (launching new countries, selling to people who aren't yet aware of it).
Besides just selling more normal Starlink subs, they also have revenue opportunities from selling their LTE cell phone product to carriers, as well as dedicated networks like the in-progress "StarShield" for the US DoD.
We could park religous fanatics and prisoners offworld? Or just drop self replecating machinery to create value. Which is the actual crux. Even for labor.. Remote or ai operated drones are cheaper.
Even with a high volume and relatively low cost launch vehicle, the actual offworld base will be hugely expensive, and no commercial enterprise can realistically expect to make a return for their investors.
A government needs to step up with the rationale that it will eventually form a tax-producing colony - but a huge investment will need to be put in till it gets there.