& +Jonathan Perrine
are expressing the economic logic of asteroid mining. It's highly valuable if
you want to use the material in space. It's not if you're thinking of bringing it down to the Earth's surface (yet - that could change, but it would take a lot of change). Hence, any current plan for extraterrestrial resource extraction must be organized around a "growing capacity in space" model. Think Von-Neumann machines (in principle, not literally). The process would be guided from down here, and would look more like conventional industry than self-replicating machines, but it would be a feedback of materials used to make more solar panels (or other energy-gathering/producing structures) and more extractive capacity, repeat. When capacity is great enough, then one can think about actually making it useful to humans. One simple use would be to just build all the stuff we would normally have to send up there (communication satellites, scientific probes, etc.). More advanced (many decades) uses could involve either importing material via advanced tech (e.g. elevators, tethers) or building habitats. But that's far, far off.
If we're wrong about the mining, and it's entirely about energy, then they still have the problem of launch costs and energy transmission to the surface. So it seems there must eventually be some sort of mining.