That fraction is still larger than the economical utilization of space.
Think about how little propellant it takes to move products on Earth. And that's not even counting for the fact that transport vehicles on Earth runs a heavy percentage of its life time while a rocket does not do that. Even Falcons spend most of their time getting ready or recycled and not on an ascend or descend trajectory.
Any real trade will not happen at these gravity tax rates.
> That fraction is still larger than the economical utilization of space.
What does this sentence even MEAN? There are economical uses of space at today's launch costs. There would be even more such uses if launch costs were a few times the cost of propellant, as the cost of air travel is.
I get the feeling you are not thinking clearly on this subject.
If launch cost were few times the cost of propellant, what economic activities become feasible in space?
Sending tourists? Sure, tourists are already up there and it costs even less propellant to drop to the ocean floor but not many people/business seemed to be doing that. Maybe with the exception of oil platforms.
Speaking of which, what oil platform will be of space? Even a floating city in space that is purely afforded by the tourist spending generates no true economic value up there - all of it is being essentially propped up by the ground. What economic incentive are there?
The only way out is to manufacture IN SITU, sourcing from locally or gravitationally less burdensome locations, like the asteroid belt. It takes less deltaV to go to the asteroid belt from LEO than it takes to get to LEO from the ground.
Trust me I've been thinking about this plenty - though probably not to any use.
A tourism analogue could be Antarctica rather than the sea floor.
Antarctica is also an analogue for manned science. Reduce costs enough and it makes sense to put people in space rather than do things remotely. There's a base at the South Pole. The cost to get there would be similar to the cost of getting to LEO, in this few-times-propellant cost scenario. Yet no one talks about automating that base, it just doesn't pencil out.
Lower launch costs will enable much larger satellites to be built, with much larger apertures of antennas and optics, and with higher bandwidth, or with much less focus on expensive mass optimization. We could see satellites in high earth orbit being maintained manually.
At a few tens of dollars per kilogram, space disposal of nuclear waste starts to make sense.
I can recommend Terra Invicta as a very realistic grand strategy game demonstrating it nicely - you will never lift the thousands of tons needed for just a single ship in your fleet to protect the Mother Earth from aggressive extraterrestrial invasion.
But plop a few mining complexes (each couple dozen tons IIRC) on the Moon or near Earth asteroid and the tables turn quite quickly. As now you can build more station from extraterrestrial resources, which mine said resources and it goes from there. :-)
