All those are either unprofitable or have much lower than trillion dollar revenue possibility in the next 50 years.
To take asteroid mining as an example: The entire platinum group metal market on Earth is only about $10-20 billion per year. Adding a huge supply is likely to crash the market price well before you drive demand up high enough to compensate for the far lower price. So platinum-group metal mining is not huge.
Mining water is also a very small market. You're primarily replacing rocket propellant for launch vehicles or maneuvering, but this is a small market. The entire commercial launch market is about $3 billion per year in revenue. Adding non-commercial launch may more than double it, but you're still talking less than $10 billion per year. And propellant (or propellant services) is going to be a small part of that. It won't help get payloads to LEO, so you're left with just providing services from LEO to GEO or something like that. Maybe for deep space missions... But even that market is very small. NASA makes up the majority of world funding for deep space exploration, about $10 billion per year optimistically. Propellant is a small fraction of that.
So for water propellant, we're looking at maybe $100 million to $1 billion per year in revenue.
For structural materials, the market is even more speculative and less proven.
Space settlements are going to be small revenue, too, for the foreseeable future. NASA human spaceflight, philanthropic, and space tourism are really the only consistent funding sources there. The settlers themselves won't be super rich as they'll need to be sustaining themselves, but let's just say we have 10,000 settlers each able to spend $100,000 for your services per year. That's just $1 billion per year. To get truly sizable, you need like a million people living in space, and it's still only $100 billion per year.
So it's primarily telecom that is the big space market. The others are much smaller and less profitable. It turns out that serving billions of Earthling consumers is where the real money is in space.
EDIT:
There are 3 big (trillion dollar) markets:
1) telecomm
2) energy
3) high speed transport (aviation)
Space can in principle address all three. The first one is the only real "slam dunk," the other two are questionable to one degree or another. SpaceX is pursuing 1 and 3.
I disagree with your statement on asteroid mining.
The profitability of mining asteroids doesn't come from bringing the metals back to earth and selling them on the traditional market: It represents the ability for spacefaring communities to build their own ships for a much lower cost than building and launching terrestrial rockets on Earth.
Furthermore - Space Stations, orbital manufacturing plants, multi-generation starships, solar arrays - all of these become incredibly cost effective when the metals used to make them become hypersaturated from asteroid mining. It's a means to an end, but by no means is it without value.
I think 1) and 3) are the only ones that do not require advances in fundamental science to achieve.
Space based energy requires a way to send the energy to the surface for monetization. The three ways to do this would be
1) Wireless transmission -- infeasible with current level tech at the distances required.
2) Wired transmission -- requires materials with very high tensile strength in quantities never before produced.
3) Deorbit batteries -- You spend more energy launching/deorbiting and distributing batteries than you gain.
High speed transport (ground to orbit, and interplanetary) have huge problems in scaling, but it mostly can be solved with current level engineering.
Wireless transmission is perfectly feasible with current tech level and distances required. In fact, we do precisely the same thing with telecommunications.
It's just a difference in scale. To get high efficiency, low cost radio amplifiers, you need to operate at relatively low frequency (think microwave oven magnetron, but modified to follow a phase and frequency input). Rectification of this has also been done. But you're going to need an enormous aperture on both sides to make it happen. That means, to me, you need on the order of 10 Gigawatts to be feasible (rough, back-of-envelope calculations). And even then, you need an enormous plot of land, preferably in the desert. So you're basically competing with cheap solar power backed by cheap batteries. Both of those are improving in cost every year. So it's possible. Feasible, even, if we had no other options. But it's not going to be competitive from what I can tell.
So it's the same type of scaling problem as #3. Except the main issue with #3 is safety: passenger aviation is just so ridiculously safe it's extremely hard to compete with.
If it's just one company doing the mining, there's no reason to crash the market. Hold 100x the world's annual demand for platinum and sell off 1% per year for 100 years. 20 Billion times 100 years isn't so bad.
I think demand for these metals is relatively inelastic, so even supplying a relatively small amount may crash the market. If you double the supply of platinum per year, you will crash the market price.
If you have that large of a stock, you could corner the market. Undercut the competition slowly, until they all go bust. Once the mining infrastructure is left in ruin, raise prices to whatever you want. It will take a while for the competition to re-mobilize the infrastructure to compete.
Platinum is a very useful catalyst. If it were much cheaper, we could do more with it.
Aluminum was a precious metal for a few decades. Royalty used it for their best forks and spoons. Now we make airliners out of it and the aluminum producers are doing just fine.
It's unlikely we'll be making airplanes out of platinum (terrible strength to weight ratio), and it's unlikely catalysts will consume as much as is used for structural applications (the global market for catalysts is itself limited, and it's not like we're going to be using orders of magnitude more catalysts of all types if the price of platinum reduces). Even still, the worldwide market for primary aluminum production is just $100 billion per year. And aluminum is a common ore. Even in space, platinum is rare.
Space mining is made out to be the pie-in-the-sky paydirt of space dreams, but it's still a much smaller market than telecoms.
Not only fuel! It would be a big boon if bateries (think Edison or lead battery not Li-ion), construction beams, antennas, heat radiators and similar heavy low-tech items can be manufactured in-space from asteroid ores so they don't need to be launched. With thousands of satellites, there will certainly be big market for such parts. Precious metals will be only a byproduct in the beginning.
To take asteroid mining as an example: The entire platinum group metal market on Earth is only about $10-20 billion per year. Adding a huge supply is likely to crash the market price well before you drive demand up high enough to compensate for the far lower price. So platinum-group metal mining is not huge.
Mining water is also a very small market. You're primarily replacing rocket propellant for launch vehicles or maneuvering, but this is a small market. The entire commercial launch market is about $3 billion per year in revenue. Adding non-commercial launch may more than double it, but you're still talking less than $10 billion per year. And propellant (or propellant services) is going to be a small part of that. It won't help get payloads to LEO, so you're left with just providing services from LEO to GEO or something like that. Maybe for deep space missions... But even that market is very small. NASA makes up the majority of world funding for deep space exploration, about $10 billion per year optimistically. Propellant is a small fraction of that.
So for water propellant, we're looking at maybe $100 million to $1 billion per year in revenue.
For structural materials, the market is even more speculative and less proven.
Space settlements are going to be small revenue, too, for the foreseeable future. NASA human spaceflight, philanthropic, and space tourism are really the only consistent funding sources there. The settlers themselves won't be super rich as they'll need to be sustaining themselves, but let's just say we have 10,000 settlers each able to spend $100,000 for your services per year. That's just $1 billion per year. To get truly sizable, you need like a million people living in space, and it's still only $100 billion per year.
So it's primarily telecom that is the big space market. The others are much smaller and less profitable. It turns out that serving billions of Earthling consumers is where the real money is in space.
EDIT:
There are 3 big (trillion dollar) markets:
1) telecomm
2) energy
3) high speed transport (aviation)
Space can in principle address all three. The first one is the only real "slam dunk," the other two are questionable to one degree or another. SpaceX is pursuing 1 and 3.