For why we'd want to go at all: there's a lot of resources up there, and pollution is much less of a concern for factories made up there. Also some material processes may be much easier in zero-gee.
But that doesn't mean it's actually worth the effort.
Access to resources. A sense of adventure. Learning.
Some people are suggesting making high quality fibre optics and pharmaceuticals in LEO already with Falcon prices:
https://en.wikipedia.org/wiki/Space_Forge
https://en.wikipedia.org/wiki/Varda_Space_Industries
While I am *extremely* skeptical, I've heard people talk about space-based solar. I mention this only so nobody adds an "and also" for that.
Ditto anyone talking about lunar He-3. This is a bad idea, "why" is long enough to be worthy of a blog post.
But if you were committed to expansionism for whatever reason, then you'd want some way to get industrial quantities of steel from mines already in space, to make the factories themselves cheaper. Possibly megastructures like an orbital ring, too.
Since you are right. All of these things are available on Earth for far cheaper, with better ROI and with far less risk of dying or getting early cancer from cosmic rays.
The real benefit is a commanding lead over geopolitical rivals in the domain of satellites and satellite platforms for hosting devices in orbit, thus securing an insurmountable national security advantage.
The second reason is that the notion of economics becomes kind of odd when you start introducing space. Space has practically infinite resources of every type imaginable. For instance one single asteroid, Psyche 16, is thought to have orders of magnitude more gold than has ever been extracted in human history. But I mean, what does this even mean economically? Obviously if you start bringing back hundreds of thousands of tons of gold, the price is going plummet. And even the viable possibility of this happening would probably send the price of gold plummeting. So... it's weird. We're in uncharted waters.
And then on top of this access to space will mean we will start expanding outward - colonies, vastly larger stations stations, and so on. And these expansions will develop their own parallel economies with their own needs/production/etc. This is all kind of like trying to predict the economics of the internet before the first cable had been laid.
But the current claustrophobic nature of the ISS was, again, not the destination. There was a grand scheme of in-orbit refueling, fuel depots, and much larger scale space architecture. Something of the ISS scale was intended as a short jumping-off point, a workers' tent analog. But our progress stalled out and the workers' tent is what we were left with.
The point I'm making here is that space in the era we're stepping into is very unlikely to look much like the one we're leaving. This is even more true as the price drops because private industry will be able to play a major role. There will be no Nixon to just cancel everything out of concerns for his political career.
Even with cheap rockets, Musk was talking about 6-digit-dollars for becoming a Martian, I don't see more than a few million people wanting to spend that much for that outcome.
If we get self-replicating robots or whatever, big space stations aren't that expensive, but also Earth is huge and you can extract minerals from seawater electrolytically and PV is already cheap, so perhaps we'd just get a load of seasteads instead: https://en.wikipedia.org/wiki/Seasteading
Really hard to say. Everyone who does space stuff talks with the same level of optimism as Musk but historically they deliver less.
But for what it's worth, I don't think Musk's going to reach Mars except in an urn, baring some surprise development in anti-aging medicine. Even though their progress is rapid by the standards of the industry, they are still slow in terms of natural human lifespan and his age.
> Have you sketched out the net present value calculation for an investment in spacex today based on that?
IMO, their market cap should be around $200bn at the moment. That's mostly Starlink, so if there's a Kessler cascade *or* if China makes a competitor that goes down to about $80-100bn
The long-term stuff about Mars or turning the moon into a factory for modular data centres is too far into the future to be worth considering.
E.g. imagine in a bet you think there's a 99% chance of something being worth $1 and a 1% chance of it being worth $1 million. What's a fair price? It's a simple calculation - 0.99 * 1 + 0.01 * 1,000,000 = ~$10,000. That's you setting a price of $10k on something that you fully expect to be worth $1 99% of the time, and still coming out just fine.
So the actual debate should not be on 'guess the future' but rather on the odds of Starship delivering and estimating the impact this would have. And I think to many the answers are fairly easy - 'very nonzero' and 'very big.' It's akin to the NVidia/Apple stories, except in this case it's being somewhat priced into the market to begin with because it's somewhat more probable, and easier to foresee.
The easy version of this is to value a company over the next 20 years of profits. The first half of that time horizon, I don't see much changing at all outside of Starlink subscribers. They've only got ~5 Mars launch windows in any given decade, and while their design philosophy is great for LEO where launch windows are daily, launching rockets to see what fails is exactly wrong for Mars.
OTOH, now to 2036, there's at least a chance AI goes boom. Perhaps even one of Musk's AI. Great for the overall economy (at least right up until it changes the economy so much that capitalism looks as obsolete as feudalism looks today, which may or may not be in that horizon), but even if it's the next industrial revolution, there's so much competition there that I expect everyone's profit margins to be almost nothing. And conversely, if any one of them does appear to be massively dominant, in comes an anti-trust case (who remembers Standard Oil?)
Same with rockets, though a "rocket boom" is perhaps an unfortunate phrasing. He finds a way to make more money than expected, just like he's already doing with Starlink? Great. Industrial espionage is a thing, and even if it wasn't, China's not got a problem with the state funding businesses to simply re-discover everyone else's secret sauce. US companies and residents may find themselves restricted from using the fruit of that work, but most of the world will just buy what's cheapest.
Still, as I said, your point is valid.
There is no backup plan.