But the first starship missions will drop 100 tons each to the surface of Mars at a cost of a few hundred million dollars each. And they will send dozens of Starships that first trip, building an camp with over a hundred explorers and scientists the first synod.
They will have thousands of tons of equipment and supplies, and their habitats will have multiple redundancies and be easily repaired.
Mars is far easier to survive on than the Moon, for example. The temperature ranges are far milder, Mars reaches 70 degrees Fahrenheit at its equator during the day. The day is the same length as ours. There is adequate solar for power, tons of water, and a plethora of other easily accessible resources from CO2 to Iron.
You might be right to do that — I’m no rocket scientist — but the target price would get a million people there for $200 billion, not your $5 quadrillion.
Yes, I also expect the first few thousand to be in easily damaged domes. I also expect them to bring some of The Boring Company equipment with them, as it is part-owned by SpaceX and the stated raison d'être of TBC being pointless in a future of fully self-driving cars.
Traffic jams with human drivers happen spontaneously when the cars get close enough that overcompensation turns into a negative spiral.
The roads are already there, electric cars are quiet, road trains are even more efficient.
I am no fan of American city design, having half encircled Davis CA on foot, having found the suddenly-terminating sidewalks in Salt Lake City, and having walked the really boring route from San Jose railway station to the hotel in the top left corner of the Apple Maps icon.
(NYC is surprisingly pedestrian friendly though).
But:
1. Musk doesn’t live in Europe, he set up TBC while stuck in a traffic jam in Los Angeles.
2. Solid car trains moving at full speed (whatever that is for the road, 20 kph for residential or much higher than the current rules for highways) use less land area than any other traffic, so some lanes can become bicycle only or whatever.
3. They can “perfectly” obey traffic lights and give way to pedestrians
4. Raised walkways are cheaper than tunnels
Would it not be easier to build large structures in orbit or at one of the Lagrange points?
But I think my favourite idea is infrared scopes in the polar craters, some of the coldest places in the solar system. You don't need a complicated JWST-style extendable sun shield or limited helium supply. You are limited in terms of direction, but that's not a bad tradeoff.
Under the sea starts out way more terraformed than Mars can ever be. It has water, gravity, and is warmer. Mineral wealth is right at hand.
The cloud tops of Venus start out way more terraformed than Mars can ever be. It has air pressure, gravity, water, carbon, sulfur, and shirtsleeve temperature.
What motivation does Mars provide that those don't?
The other option is the Moon, which has even less atmosphere and even bigger temperature swings than Mars.
But the point was, if you haven't even proven you can settle a mildly challenging environment, your odds on an actually difficult one don't look good.
Venus, you could only settle by bringing in everything from outside unless and until you can convert the atmosphere in a large way into building materials — Mars at least you only need to convert it into fuel, because you can do at least some of your construction from rocks.
On Venus, plastics, carbon fiber, water, buoyancy gas, and breathing air (I repeat myself) can be made directly from the air and clouds. Plastic and carbon fiber gives you building materials. Robots can gather minerals from the surface and deliver them by balloon to the cloud tops. Insolation provides abundant power, moreso than here; or, a lightweight, unshielded nuke plant may be suspended a mile or more below industrial plant, supported on its own balloon.
Mars will be much more unpleasant than Antarctica. We don't even know whether people can live for long in Mars gravity. We know that long weightlessness is quite harmful.
With any luck, things you learn actually doing A, and then A' that is 10 times harder, and then A'' that is 100 times harder, will all turn out to be useful, even necessary, in tackling B. Failure is always an option, but there is no point in choosing it at the outset.
If you think there will be a million people colony on Mars in your lifetime than you are not in touch with the physics of this kind of endeavor. All of our GDP for the next 50 years pooled together would likely not be enough to pull off a feat like that. The scale we're talking about here is too large to even contemplate.
10 people in a shitty little dome, maybe. Right up to the moment they die because of some small mishap.