> as clearly nobody here has any real idea to what extent there will be exports from Mars within the next 30 years.
Conditional on there being a Mars colony in 30 years, then there will almost certainly be mineral and food exports from Mars to the rest of the solar system other than Earth in another 10.
You know that Mars atmosphere don't capture oxygen right? [1]
No way to grow food there unless you export a whole lot of greenhouses and set up an artificial biosphere, but without the conditions that we take for granted on earth.
This is already hard to do in deserts or in the Polar regions, where we have plenty of oxygen and free moisture flowing in the atmosphere.
It's not, but a huge pressurized dome would be pretty much expensive, I do not think a colony on Mars would be able to produce more than subsistence level for the pioneers.
There has already been consideration of producing polymers on Mars from the atmosphere. Agricultural domes would not have to be reliable as living spaces, so these could be built cheaply as inflatable structures. So mars could build its own greenhouses.
Conditional on there being a Mars colony in 30 years, then there will almost certainly be mineral and food exports from Mars to the rest of the solar system other than Earth in another 10.